diff --git a/.env.example b/.env.example
index f38a881..9974db3 100644
--- a/.env.example
+++ b/.env.example
@@ -36,6 +36,20 @@ BACKEND_PORT=8001
 REDIS_PORT=6379
 
 
+# ── AUTH ─────────────────────────────────────────────────────────────────────
+
+# Secret key used to sign JWT tokens. Generate a strong random value for
+# production (e.g. `openssl rand -base64 32`). The default is a deterministic
+# placeholder acceptable only for local/homelab use.
+# SECRET_KEY=change-me-to-a-random-string
+
+# How long access and refresh tokens stay valid. Access tokens are short-lived
+# and silently refreshed by the frontend; refresh tokens let a session survive
+# across browser restarts.
+# ACCESS_TOKEN_EXPIRE_MINUTES=60
+# REFRESH_TOKEN_EXPIRE_DAYS=30
+
+
 # ── CORS ─────────────────────────────────────────────────────────────────────
 
 # Comma-separated list of allowed origins for direct browser access to the
diff --git a/backend/alembic/versions/0009_users_and_auth.py b/backend/alembic/versions/0009_users_and_auth.py
new file mode 100644
index 0000000..1948233
--- /dev/null
+++ b/backend/alembic/versions/0009_users_and_auth.py
@@ -0,0 +1,144 @@
+"""users table and user_id foreign keys
+
+Revision ID: 0009_users_and_auth
+Revises: 0008_photos_date_warning
+Create Date: 2026-04-12
+
+Introduces multi-user support:
+  1. Creates the `users` table.
+  2. Adds `user_id` FK columns to photos, folders, source_roots, heaps, tags.
+  3. For existing installs: creates a default admin user and assigns all
+     existing rows to that user. The generated password is printed to the
+     backend logs — the admin should change it on first login.
+  4. Replaces the unique constraint on tags (name, kind) with
+     (name, kind, user_id) so each user can have their own tags.
+"""
+from typing import Sequence, Union
+import uuid
+import secrets
+
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = "0009_users_and_auth"
+down_revision: Union[str, None] = "0008_photos_date_warning"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+
+    # 1. Create users table (IF NOT EXISTS — safe on fresh installs where
+    #    init_db's create_all has already laid down the schema).
+    conn.execute(sa.text("""
+        CREATE TABLE IF NOT EXISTS users (
+            id VARCHAR NOT NULL PRIMARY KEY,
+            username VARCHAR(50) NOT NULL UNIQUE,
+            email VARCHAR UNIQUE,
+            hashed_password VARCHAR NOT NULL,
+            role VARCHAR NOT NULL DEFAULT 'user',
+            is_active BOOLEAN NOT NULL DEFAULT true,
+            created_at TIMESTAMP WITHOUT TIME ZONE DEFAULT now(),
+            media_path VARCHAR NOT NULL
+        )
+    """))
+    conn.execute(sa.text(
+        "CREATE INDEX IF NOT EXISTS ix_users_username ON users (username)"
+    ))
+
+    # 2. Add user_id columns (nullable initially for the data migration)
+    for table in ("photos", "folders", "source_roots", "heaps", "tags"):
+        conn.execute(sa.text(
+            f"ALTER TABLE {table} ADD COLUMN IF NOT EXISTS user_id VARCHAR"
+        ))
+        conn.execute(sa.text(
+            f"CREATE INDEX IF NOT EXISTS ix_{table}_user_id ON {table} (user_id)"
+        ))
+        # FK — check if it already exists before adding
+        fk_name = f"fk_{table}_user_id"
+        fk_exists = conn.execute(sa.text(
+            "SELECT 1 FROM information_schema.table_constraints "
+            "WHERE constraint_name = :name AND table_name = :tbl"
+        ), {"name": fk_name, "tbl": table}).scalar()
+        if not fk_exists:
+            conn.execute(sa.text(
+                f"ALTER TABLE {table} ADD CONSTRAINT {fk_name} "
+                f"FOREIGN KEY (user_id) REFERENCES users(id)"
+            ))
+
+    # 3. Data migration: if rows exist, create a default admin and assign
+    conn = op.get_bind()
+    photo_count = conn.execute(sa.text("SELECT COUNT(*) FROM photos")).scalar()
+
+    if photo_count > 0:
+        admin_id = str(uuid.uuid4())
+        generated_password = secrets.token_urlsafe(16)
+
+        # Hash the password using passlib at migration time
+        from passlib.context import CryptContext
+        pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+        hashed = pwd_context.hash(generated_password)
+
+        # The default admin's media_path is the legacy /photos root
+        conn.execute(
+            sa.text(
+                "INSERT INTO users (id, username, hashed_password, role, media_path) "
+                "VALUES (:id, :username, :hashed, :role, :media_path)"
+            ),
+            {
+                "id": admin_id,
+                "username": "admin",
+                "hashed": hashed,
+                "role": "admin",
+                "media_path": "/photos",
+            },
+        )
+
+        # Assign all existing rows to the default admin
+        for table in ("photos", "folders", "source_roots", "heaps", "tags"):
+            conn.execute(
+                sa.text(f"UPDATE {table} SET user_id = :uid WHERE user_id IS NULL"),
+                {"uid": admin_id},
+            )
+
+        import logging
+        logger = logging.getLogger("alembic.migration")
+        logger.warning(
+            f"=== MIGRATION 0009 === Default admin created. "
+            f"Username: admin | Password: {generated_password} | "
+            f"Change this password on first login!"
+        )
+
+    # 4. Replace tag unique constraint to include user_id
+    # Check whether the old constraint exists before trying to drop it
+    # (on fresh installs create_all creates the new constraint directly).
+    old_uq_exists = conn.execute(sa.text(
+        "SELECT 1 FROM information_schema.table_constraints "
+        "WHERE constraint_name = 'uq_tags_name_kind' AND table_name = 'tags'"
+    )).scalar()
+    if old_uq_exists:
+        op.drop_constraint("uq_tags_name_kind", "tags", type_="unique")
+
+    new_uq_exists = conn.execute(sa.text(
+        "SELECT 1 FROM information_schema.table_constraints "
+        "WHERE constraint_name = 'uq_tags_name_kind_user' AND table_name = 'tags'"
+    )).scalar()
+    if not new_uq_exists:
+        op.create_unique_constraint("uq_tags_name_kind_user", "tags", ["name", "kind", "user_id"])
+
+
+def downgrade() -> None:
+    # Reverse the tag constraint
+    op.drop_constraint("uq_tags_name_kind_user", "tags", type_="unique")
+    op.create_unique_constraint("uq_tags_name_kind", "tags", ["name", "kind"])
+
+    # Drop user_id columns and FKs
+    for table in ("photos", "folders", "source_roots", "heaps", "tags"):
+        op.drop_constraint(f"fk_{table}_user_id", table, type_="foreignkey")
+        op.drop_index(f"ix_{table}_user_id", table_name=table)
+        op.drop_column(table, "user_id")
+
+    # Drop users table
+    op.drop_index("ix_users_username", table_name="users")
+    op.drop_table("users")
diff --git a/backend/app/auth.py b/backend/app/auth.py
new file mode 100644
index 0000000..34050d4
--- /dev/null
+++ b/backend/app/auth.py
@@ -0,0 +1,47 @@
+"""
+Authentication utilities — password hashing and JWT token management.
+"""
+from datetime import datetime, timedelta, timezone
+
+from jose import jwt, JWTError
+from passlib.context import CryptContext
+
+from app.config import settings
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+ALGORITHM = "HS256"
+
+
+def hash_password(plain: str) -> str:
+    return pwd_context.hash(plain)
+
+
+def verify_password(plain: str, hashed: str) -> bool:
+    return pwd_context.verify(plain, hashed)
+
+
+def create_access_token(user_id: str, role: str) -> str:
+    expire = datetime.now(timezone.utc) + timedelta(minutes=settings.access_token_expire_minutes)
+    payload = {
+        "sub": user_id,
+        "role": role,
+        "exp": expire,
+        "type": "access",
+    }
+    return jwt.encode(payload, settings.secret_key, algorithm=ALGORITHM)
+
+
+def create_refresh_token(user_id: str) -> str:
+    expire = datetime.now(timezone.utc) + timedelta(days=settings.refresh_token_expire_days)
+    payload = {
+        "sub": user_id,
+        "exp": expire,
+        "type": "refresh",
+    }
+    return jwt.encode(payload, settings.secret_key, algorithm=ALGORITHM)
+
+
+def decode_token(token: str) -> dict:
+    """Decode and validate a JWT. Raises JWTError on any problem."""
+    return jwt.decode(token, settings.secret_key, algorithms=[ALGORITHM])
diff --git a/backend/app/config.py b/backend/app/config.py
index 025bd6f..d8308ef 100644
--- a/backend/app/config.py
+++ b/backend/app/config.py
@@ -127,6 +127,17 @@ class Settings(BaseSettings):
     # ERROR, CRITICAL). Bumped from INFO when chasing a problem.
     log_level: str = Field(default="INFO", env="LOG_LEVEL")
 
+    # Auth — JWT signing key. Set SECRET_KEY in .env for production.
+    # If unset, a deterministic fallback is used (acceptable for
+    # single-machine homelab deploys, but set a real key if the instance
+    # is network-exposed).
+    secret_key: str = Field(
+        default="mulita-dev-secret-change-me",
+        env="SECRET_KEY",
+    )
+    access_token_expire_minutes: int = Field(default=60, env="ACCESS_TOKEN_EXPIRE_MINUTES")
+    refresh_token_expire_days: int = Field(default=30, env="REFRESH_TOKEN_EXPIRE_DAYS")
+
     @property
     def cors_origins(self) -> list[str]:
         """Parse the ALLOWED_ORIGINS env var into a list. Accepts:
diff --git a/backend/app/database.py b/backend/app/database.py
index 32211a8..670571b 100644
--- a/backend/app/database.py
+++ b/backend/app/database.py
@@ -100,7 +100,7 @@ async def init_db():
     """Initialize database, create tables if they don't exist"""
     async with engine.begin() as conn:
         # Import all models to register them with Base
-        from app.models import Photo, Folder, SourceRoot, Tag, PhotoTag, Heap, HeapPhoto, Embedding
+        from app.models import User, Photo, Folder, SourceRoot, Tag, PhotoTag, Heap, HeapPhoto, Embedding
 
         # Postgres: ensure pgvector is available before create_all touches
         # any Vector columns (added in later PRs but the extension is cheap
diff --git a/backend/app/dependencies.py b/backend/app/dependencies.py
new file mode 100644
index 0000000..001fbab
--- /dev/null
+++ b/backend/app/dependencies.py
@@ -0,0 +1,132 @@
+"""
+FastAPI dependencies for authentication and user-scoped data access.
+"""
+from fastapi import Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordBearer
+from jose import JWTError
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload
+
+from app.auth import decode_token
+from app.database import get_db
+from app.models.user import User
+from app.models.photos import Photo
+from app.models.folders import Folder, SourceRoot
+from app.models.heaps import Heap
+from app.models.tags import Tag
+
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/v1/auth/login")
+
+
+async def get_current_user(
+    token: str = Depends(oauth2_scheme),
+    db: AsyncSession = Depends(get_db),
+) -> User:
+    """Decode JWT, look up user, raise 401 if invalid or inactive."""
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Invalid or expired token",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = decode_token(token)
+        user_id: str = payload.get("sub")
+        token_type: str = payload.get("type")
+        if user_id is None or token_type != "access":
+            raise credentials_exception
+    except JWTError:
+        raise credentials_exception
+
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if user is None or not user.is_active:
+        raise credentials_exception
+    return user
+
+
+async def require_admin(
+    user: User = Depends(get_current_user),
+) -> User:
+    """Raise 403 if user is not an admin."""
+    if user.role != "admin":
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Admin privileges required",
+        )
+    return user
+
+
+# ---------------------------------------------------------------------------
+# User-scoped query helpers
+# ---------------------------------------------------------------------------
+
+def user_photos_query(user: User):
+    """Base select for photos owned by user, with tags eager-loaded."""
+    return (
+        select(Photo)
+        .options(selectinload(Photo.tags))
+        .where(Photo.user_id == user.id)
+    )
+
+
+async def get_user_photo(
+    photo_id: str,
+    user: User,
+    db: AsyncSession,
+) -> Photo:
+    """Fetch a single photo by ID, scoped to the user. Raises 404."""
+    result = await db.execute(
+        select(Photo)
+        .options(selectinload(Photo.tags))
+        .where(Photo.id == photo_id, Photo.user_id == user.id)
+    )
+    photo = result.scalar_one_or_none()
+    if photo is None:
+        raise HTTPException(status_code=404, detail="Photo not found")
+    return photo
+
+
+async def get_user_folder(
+    folder_id: str,
+    user: User,
+    db: AsyncSession,
+) -> Folder:
+    """Fetch a single folder by ID, scoped to the user. Raises 404."""
+    result = await db.execute(
+        select(Folder).where(Folder.id == folder_id, Folder.user_id == user.id)
+    )
+    folder = result.scalar_one_or_none()
+    if folder is None:
+        raise HTTPException(status_code=404, detail="Folder not found")
+    return folder
+
+
+async def get_user_heap(
+    heap_id: str,
+    user: User,
+    db: AsyncSession,
+) -> Heap:
+    """Fetch a single heap by ID, scoped to the user. Raises 404."""
+    result = await db.execute(
+        select(Heap).where(Heap.id == heap_id, Heap.user_id == user.id)
+    )
+    heap = result.scalar_one_or_none()
+    if heap is None:
+        raise HTTPException(status_code=404, detail="Heap not found")
+    return heap
+
+
+async def get_user_tag(
+    tag_id: str,
+    user: User,
+    db: AsyncSession,
+) -> Tag:
+    """Fetch a single tag by ID, scoped to the user. Raises 404."""
+    result = await db.execute(
+        select(Tag).where(Tag.id == tag_id, Tag.user_id == user.id)
+    )
+    tag = result.scalar_one_or_none()
+    if tag is None:
+        raise HTTPException(status_code=404, detail="Tag not found")
+    return tag
diff --git a/backend/app/main.py b/backend/app/main.py
index 4ceaa66..cecc468 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -11,7 +11,7 @@ import os
 
 from app.config import settings
 from app.database import init_db
-from app.routers import photos, folders, heaps, tags, discard, library, search
+from app.routers import photos, folders, heaps, tags, discard, library, search, auth, admin
 from app.services.scanner import start_initial_scan, bootstrap_default_source_root
 from app.services.cleanup import cleanup_data_integrity
 
@@ -85,6 +85,8 @@ if os.path.exists("/data/thumbs"):
     app.mount("/thumbs", StaticFiles(directory="/data/thumbs"), name="thumbs")
 
 # Include routers
+app.include_router(auth.router, prefix="/api/v1/auth", tags=["auth"])
+app.include_router(admin.router, prefix="/api/v1/admin", tags=["admin"])
 app.include_router(photos.router, prefix="/api/v1/photos", tags=["photos"])
 app.include_router(folders.router, prefix="/api/v1/folders", tags=["folders"])
 app.include_router(heaps.router, prefix="/api/v1/heaps", tags=["heaps"])
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index 8d45771..945cc70 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -1,6 +1,7 @@
 """
 Database models for Mulita
 """
+from app.models.user import User
 from app.models.photos import Photo
 from app.models.folders import Folder, SourceRoot
 from app.models.tags import Tag, PhotoTag
@@ -10,6 +11,7 @@ from app.models.ocr_text import OCRText
 from app.models.face_embedding import FaceEmbedding
 
 __all__ = [
+    'User',
     'Photo',
     'Folder',
     'SourceRoot',
diff --git a/backend/app/models/folders.py b/backend/app/models/folders.py
index 51cfb6b..036a057 100644
--- a/backend/app/models/folders.py
+++ b/backend/app/models/folders.py
@@ -10,13 +10,16 @@ from app.database import Base
 
 class SourceRoot(Base):
     __tablename__ = 'source_roots'
-    
+
     id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
     name = Column(String, nullable=False)
     path = Column(String, unique=True, nullable=False)
     is_active = Column(Boolean, default=True)
     added_at = Column(DateTime, server_default=func.now())
-    
+
+    # Owner
+    user_id = Column(String, ForeignKey('users.id'), nullable=True, index=True)
+
     # Relationships
     folders = relationship("Folder", back_populates="source_root")
 
@@ -28,6 +31,9 @@ class Folder(Base):
     path = Column(String, unique=True, nullable=False)
     parent_id = Column(String, ForeignKey('folders.id'))
     source_root_id = Column(String, ForeignKey('source_roots.id'))
+
+    # Owner
+    user_id = Column(String, ForeignKey('users.id'), nullable=True, index=True)
     photo_count = Column(Integer, default=0)
     last_scanned = Column(DateTime)
 
diff --git a/backend/app/models/heaps.py b/backend/app/models/heaps.py
index 470fda2..9a46aac 100644
--- a/backend/app/models/heaps.py
+++ b/backend/app/models/heaps.py
@@ -22,12 +22,15 @@ heap_photos = Table(
 
 class Heap(Base):
     __tablename__ = 'heaps'
-    
+
     id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
     name = Column(String, nullable=False)
     created_at = Column(DateTime, server_default=func.now())
     updated_at = Column(DateTime, onupdate=func.now())
     is_active = Column(Boolean, default=False)  # For active heap feature
+
+    # Owner
+    user_id = Column(String, ForeignKey('users.id'), nullable=True, index=True)
     
     # Relationships
     photos = relationship("Photo", secondary=heap_photos, backref="heaps")
diff --git a/backend/app/models/photos.py b/backend/app/models/photos.py
index e5ddf6c..df76bae 100644
--- a/backend/app/models/photos.py
+++ b/backend/app/models/photos.py
@@ -14,6 +14,9 @@ class Photo(Base):
     # Primary key
     id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
     
+    # Owner
+    user_id = Column(String, ForeignKey('users.id'), nullable=True, index=True)
+
     # File information
     filepath = Column(String, unique=True, nullable=False)
     filename = Column(String, nullable=False)
diff --git a/backend/app/models/tags.py b/backend/app/models/tags.py
index 6cb50c2..ff6fe8c 100644
--- a/backend/app/models/tags.py
+++ b/backend/app/models/tags.py
@@ -30,13 +30,16 @@ photo_tags = Table(
 class Tag(Base):
     __tablename__ = 'tags'
     __table_args__ = (
-        UniqueConstraint('name', 'kind', name='uq_tags_name_kind'),
+        UniqueConstraint('name', 'kind', 'user_id', name='uq_tags_name_kind_user'),
     )
 
     id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
     name = Column(String, nullable=False, index=True)
     color = Column(String)  # Hex color code for UI display
 
+    # Owner
+    user_id = Column(String, ForeignKey('users.id'), nullable=True, index=True)
+
     # Tag classification
     kind = Column(String, nullable=False, default='user', index=True)
     # kind values: 'user' | 'object' | 'scene' | 'face_cluster'
diff --git a/backend/app/models/user.py b/backend/app/models/user.py
new file mode 100644
index 0000000..917bd53
--- /dev/null
+++ b/backend/app/models/user.py
@@ -0,0 +1,23 @@
+"""
+User model definition
+"""
+from sqlalchemy import Column, String, Boolean, DateTime
+from sqlalchemy.sql import func
+import uuid
+
+from app.database import Base
+
+
+class User(Base):
+    __tablename__ = 'users'
+
+    id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
+    username = Column(String(50), unique=True, nullable=False, index=True)
+    email = Column(String, unique=True, nullable=True)
+    hashed_password = Column(String, nullable=False)
+    role = Column(String, nullable=False, default='user')  # 'admin' | 'user'
+    is_active = Column(Boolean, default=True)
+    created_at = Column(DateTime, server_default=func.now())
+
+    # Absolute path to this user's photo directory (e.g., "/photos/daniel")
+    media_path = Column(String, nullable=False)
diff --git a/backend/app/routers/admin.py b/backend/app/routers/admin.py
new file mode 100644
index 0000000..27b04fc
--- /dev/null
+++ b/backend/app/routers/admin.py
@@ -0,0 +1,260 @@
+"""
+Admin router — user management and app configuration.
+All endpoints require admin role.
+"""
+import os
+import logging
+from typing import Optional, List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel
+from sqlalchemy import select, func as sa_func
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.auth import hash_password
+from app.database import get_db
+from app.dependencies import require_admin
+from app.models.user import User
+from app.models.photos import Photo
+from app.models.folders import SourceRoot
+from app.config import settings
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter()
+
+
+# ---------------------------------------------------------------------------
+# Schemas
+# ---------------------------------------------------------------------------
+
+class CreateUserRequest(BaseModel):
+    username: str
+    password: str
+    role: str = "user"  # 'admin' | 'user'
+
+class UpdateUserRequest(BaseModel):
+    role: Optional[str] = None
+    is_active: Optional[bool] = None
+    new_password: Optional[str] = None
+
+class UserDetailResponse(BaseModel):
+    id: str
+    username: str
+    email: Optional[str]
+    role: str
+    is_active: bool
+    media_path: str
+    created_at: Optional[str]
+    photo_count: int = 0
+
+class UserListResponse(BaseModel):
+    users: List[UserDetailResponse]
+    total: int
+
+
+# ---------------------------------------------------------------------------
+# User CRUD
+# ---------------------------------------------------------------------------
+
+@router.get("/users", response_model=UserListResponse)
+async def list_users(
+    admin: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+):
+    """List all users with their photo counts."""
+    result = await db.execute(select(User).order_by(User.created_at))
+    users = result.scalars().all()
+
+    user_list = []
+    for u in users:
+        count_result = await db.execute(
+            select(sa_func.count(Photo.id)).where(Photo.user_id == u.id)
+        )
+        photo_count = count_result.scalar() or 0
+
+        user_list.append(UserDetailResponse(
+            id=u.id,
+            username=u.username,
+            email=u.email,
+            role=u.role,
+            is_active=u.is_active,
+            media_path=u.media_path,
+            created_at=u.created_at.isoformat() if u.created_at else None,
+            photo_count=photo_count,
+        ))
+
+    return UserListResponse(users=user_list, total=len(user_list))
+
+
+@router.post("/users", status_code=201, response_model=UserDetailResponse)
+async def create_user(
+    body: CreateUserRequest,
+    admin: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+):
+    """Create a new user. Creates their media directory and source root."""
+    if body.role not in ("admin", "user"):
+        raise HTTPException(status_code=400, detail="Role must be 'admin' or 'user'")
+    if len(body.username.strip()) < 2:
+        raise HTTPException(status_code=400, detail="Username must be at least 2 characters")
+    if len(body.password) < 6:
+        raise HTTPException(status_code=400, detail="Password must be at least 6 characters")
+
+    # Check for duplicate username
+    existing = await db.execute(
+        select(User).where(User.username == body.username.strip())
+    )
+    if existing.scalar_one_or_none() is not None:
+        raise HTTPException(status_code=409, detail="Username already taken")
+
+    media_path = os.path.join(settings.photo_dirs, body.username.strip())
+    os.makedirs(media_path, exist_ok=True)
+
+    user = User(
+        username=body.username.strip(),
+        hashed_password=hash_password(body.password),
+        role=body.role,
+        media_path=media_path,
+    )
+    db.add(user)
+    await db.flush()  # get user.id before creating source root
+
+    source_root = SourceRoot(
+        name=f"{user.username}'s Library",
+        path=media_path,
+        user_id=user.id,
+    )
+    db.add(source_root)
+    await db.commit()
+
+    logger.info(f"Admin '{admin.username}' created user '{user.username}' (role={user.role})")
+
+    return UserDetailResponse(
+        id=user.id,
+        username=user.username,
+        email=user.email,
+        role=user.role,
+        is_active=user.is_active,
+        media_path=user.media_path,
+        created_at=user.created_at.isoformat() if user.created_at else None,
+        photo_count=0,
+    )
+
+
+@router.get("/users/{user_id}", response_model=UserDetailResponse)
+async def get_user(
+    user_id: str,
+    admin: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+):
+    """Get a single user's details."""
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if user is None:
+        raise HTTPException(status_code=404, detail="User not found")
+
+    count_result = await db.execute(
+        select(sa_func.count(Photo.id)).where(Photo.user_id == user.id)
+    )
+    photo_count = count_result.scalar() or 0
+
+    return UserDetailResponse(
+        id=user.id,
+        username=user.username,
+        email=user.email,
+        role=user.role,
+        is_active=user.is_active,
+        media_path=user.media_path,
+        created_at=user.created_at.isoformat() if user.created_at else None,
+        photo_count=photo_count,
+    )
+
+
+@router.patch("/users/{user_id}", response_model=UserDetailResponse)
+async def update_user(
+    user_id: str,
+    body: UpdateUserRequest,
+    admin: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+):
+    """Update a user's role, active status, or password."""
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if user is None:
+        raise HTTPException(status_code=404, detail="User not found")
+
+    if body.role is not None:
+        if body.role not in ("admin", "user"):
+            raise HTTPException(status_code=400, detail="Role must be 'admin' or 'user'")
+        # Prevent demoting the last admin
+        if user.role == "admin" and body.role == "user":
+            admin_count = (await db.execute(
+                select(sa_func.count(User.id)).where(User.role == "admin", User.is_active == True)
+            )).scalar()
+            if admin_count <= 1:
+                raise HTTPException(status_code=400, detail="Cannot demote the last admin")
+        user.role = body.role
+
+    if body.is_active is not None:
+        # Prevent deactivating the last admin
+        if user.role == "admin" and not body.is_active:
+            admin_count = (await db.execute(
+                select(sa_func.count(User.id)).where(User.role == "admin", User.is_active == True)
+            )).scalar()
+            if admin_count <= 1:
+                raise HTTPException(status_code=400, detail="Cannot deactivate the last admin")
+        user.is_active = body.is_active
+
+    if body.new_password is not None:
+        if len(body.new_password) < 6:
+            raise HTTPException(status_code=400, detail="Password must be at least 6 characters")
+        user.hashed_password = hash_password(body.new_password)
+
+    await db.commit()
+
+    count_result = await db.execute(
+        select(sa_func.count(Photo.id)).where(Photo.user_id == user.id)
+    )
+    photo_count = count_result.scalar() or 0
+
+    return UserDetailResponse(
+        id=user.id,
+        username=user.username,
+        email=user.email,
+        role=user.role,
+        is_active=user.is_active,
+        media_path=user.media_path,
+        created_at=user.created_at.isoformat() if user.created_at else None,
+        photo_count=photo_count,
+    )
+
+
+@router.delete("/users/{user_id}")
+async def delete_user(
+    user_id: str,
+    admin: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+):
+    """Soft-delete a user by deactivating them. Media is preserved."""
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if user is None:
+        raise HTTPException(status_code=404, detail="User not found")
+
+    if user.id == admin.id:
+        raise HTTPException(status_code=400, detail="Cannot delete yourself")
+
+    # Prevent deleting the last admin
+    if user.role == "admin":
+        admin_count = (await db.execute(
+            select(sa_func.count(User.id)).where(User.role == "admin", User.is_active == True)
+        )).scalar()
+        if admin_count <= 1:
+            raise HTTPException(status_code=400, detail="Cannot delete the last admin")
+
+    user.is_active = False
+    await db.commit()
+
+    logger.info(f"Admin '{admin.username}' deactivated user '{user.username}'")
+    return {"status": "ok", "detail": f"User '{user.username}' deactivated"}
diff --git a/backend/app/routers/auth.py b/backend/app/routers/auth.py
new file mode 100644
index 0000000..86a60f0
--- /dev/null
+++ b/backend/app/routers/auth.py
@@ -0,0 +1,200 @@
+"""
+Authentication router — login, token refresh, profile, first-run setup.
+"""
+import os
+import logging
+from typing import Optional
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel
+from sqlalchemy import select, func as sa_func
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.auth import hash_password, verify_password, create_access_token, create_refresh_token, decode_token
+from app.database import get_db
+from app.dependencies import get_current_user
+from app.models.user import User
+from app.models.folders import SourceRoot
+from app.config import settings
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter()
+
+
+# ---------------------------------------------------------------------------
+# Request / response schemas
+# ---------------------------------------------------------------------------
+
+class LoginRequest(BaseModel):
+    username: str
+    password: str
+
+class TokenResponse(BaseModel):
+    access_token: str
+    refresh_token: str
+    token_type: str = "bearer"
+
+class RefreshRequest(BaseModel):
+    refresh_token: str
+
+class UserResponse(BaseModel):
+    id: str
+    username: str
+    email: Optional[str]
+    role: str
+    is_active: bool
+    created_at: Optional[str]
+
+class SetupRequest(BaseModel):
+    username: str
+    password: str
+
+class ChangePasswordRequest(BaseModel):
+    current_password: str
+    new_password: str
+
+
+# ---------------------------------------------------------------------------
+# Endpoints
+# ---------------------------------------------------------------------------
+
+@router.post("/login", response_model=TokenResponse)
+async def login(body: LoginRequest, db: AsyncSession = Depends(get_db)):
+    """Authenticate with username + password, receive JWT tokens."""
+    result = await db.execute(
+        select(User).where(User.username == body.username)
+    )
+    user = result.scalar_one_or_none()
+
+    if user is None or not verify_password(body.password, user.hashed_password):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Invalid username or password",
+        )
+    if not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Account is deactivated",
+        )
+
+    return TokenResponse(
+        access_token=create_access_token(user.id, user.role),
+        refresh_token=create_refresh_token(user.id),
+    )
+
+
+@router.post("/refresh", response_model=TokenResponse)
+async def refresh_token(body: RefreshRequest, db: AsyncSession = Depends(get_db)):
+    """Exchange a valid refresh token for a new access + refresh pair."""
+    try:
+        payload = decode_token(body.refresh_token)
+        if payload.get("type") != "refresh":
+            raise ValueError("not a refresh token")
+        user_id = payload["sub"]
+    except Exception:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Invalid or expired refresh token",
+        )
+
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if user is None or not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="User not found or deactivated",
+        )
+
+    return TokenResponse(
+        access_token=create_access_token(user.id, user.role),
+        refresh_token=create_refresh_token(user.id),
+    )
+
+
+@router.get("/me", response_model=UserResponse)
+async def get_me(current_user: User = Depends(get_current_user)):
+    """Return the authenticated user's profile."""
+    return UserResponse(
+        id=current_user.id,
+        username=current_user.username,
+        email=current_user.email,
+        role=current_user.role,
+        is_active=current_user.is_active,
+        created_at=current_user.created_at.isoformat() if current_user.created_at else None,
+    )
+
+
+@router.post("/change-password")
+async def change_password(
+    body: ChangePasswordRequest,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Change the authenticated user's password."""
+    if not verify_password(body.current_password, current_user.hashed_password):
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Current password is incorrect",
+        )
+    current_user.hashed_password = hash_password(body.new_password)
+    await db.commit()
+    return {"status": "ok"}
+
+
+@router.post("/setup", response_model=TokenResponse, status_code=201)
+async def setup(body: SetupRequest, db: AsyncSession = Depends(get_db)):
+    """First-run only: create the initial admin account.
+
+    Returns 409 if any user already exists. This endpoint is
+    unauthenticated by design — it can only run once.
+    """
+    count = (await db.execute(select(sa_func.count(User.id)))).scalar()
+    if count > 0:
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="Setup already completed — users exist",
+        )
+
+    if len(body.username.strip()) < 2:
+        raise HTTPException(status_code=400, detail="Username must be at least 2 characters")
+    if len(body.password) < 6:
+        raise HTTPException(status_code=400, detail="Password must be at least 6 characters")
+
+    media_path = os.path.join(settings.photo_dirs, body.username.strip())
+    os.makedirs(media_path, exist_ok=True)
+
+    user = User(
+        username=body.username.strip(),
+        hashed_password=hash_password(body.password),
+        role="admin",
+        media_path=media_path,
+    )
+    db.add(user)
+
+    # Create a source root for the new admin's media directory
+    source_root = SourceRoot(
+        name=f"{user.username}'s Library",
+        path=media_path,
+        user_id=user.id,
+    )
+    db.add(source_root)
+    await db.commit()
+
+    logger.info(f"Initial admin account created: {user.username}")
+
+    return TokenResponse(
+        access_token=create_access_token(user.id, user.role),
+        refresh_token=create_refresh_token(user.id),
+    )
+
+
+@router.get("/status")
+async def auth_status(db: AsyncSession = Depends(get_db)):
+    """Public endpoint: returns whether setup has been completed.
+
+    The frontend calls this to decide whether to show the setup page
+    or the login page.
+    """
+    count = (await db.execute(select(sa_func.count(User.id)))).scalar()
+    return {"setup_completed": count > 0}
diff --git a/backend/app/routers/discard.py b/backend/app/routers/discard.py
index b5c0c2d..15bdd0d 100644
--- a/backend/app/routers/discard.py
+++ b/backend/app/routers/discard.py
@@ -9,25 +9,27 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.database import get_db
 from app.models import Photo
+from app.models.user import User
+from app.dependencies import get_current_user
 
 logger = logging.getLogger(__name__)
 
 router = APIRouter()
 
 @router.get("")
-async def list_discarded(db: AsyncSession = Depends(get_db)):
+async def list_discarded(db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """List discarded photos"""
     result = await db.execute(
-        select(Photo).where(Photo.is_discarded == True)
+        select(Photo).where(Photo.is_discarded == True, Photo.user_id == current_user.id)
     )
     photos = result.scalars().all()
     return photos
 
 @router.post("/restore")
-async def restore_photos(photo_ids: list[str], db: AsyncSession = Depends(get_db)):
+async def restore_photos(photo_ids: list[str], db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Restore photos from the discard pile"""
     result = await db.execute(
-        select(Photo).where(and_(Photo.id.in_(photo_ids), Photo.is_discarded == True))
+        select(Photo).where(and_(Photo.id.in_(photo_ids), Photo.is_discarded == True, Photo.user_id == current_user.id))
     )
     photos = result.scalars().all()
 
@@ -39,12 +41,12 @@ async def restore_photos(photo_ids: list[str], db: AsyncSession = Depends(get_db
     return {"status": "success", "restored": len(photos)}
 
 @router.delete("/empty")
-async def empty_discard(db: AsyncSession = Depends(get_db)):
+async def empty_discard(db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Permanently delete all discarded photos and unlink their files from
     disk. Failures on individual files are logged but don't abort the batch.
     """
     result = await db.execute(
-        select(Photo).where(Photo.is_discarded == True)
+        select(Photo).where(Photo.is_discarded == True, Photo.user_id == current_user.id)
     )
     photos = result.scalars().all()
     return await _permanently_delete(db, photos)
@@ -54,6 +56,7 @@ async def empty_discard(db: AsyncSession = Depends(get_db)):
 async def delete_discarded(
     photo_ids: list[str] = Body(..., embed=True),
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Permanently delete a specific subset of discarded photos. The photos
     must already be in the discard pile — non-discarded ids are skipped so
@@ -63,7 +66,7 @@ async def delete_discarded(
         return {"status": "success", "deleted": 0, "file_errors": 0}
     result = await db.execute(
         select(Photo).where(
-            and_(Photo.id.in_(photo_ids), Photo.is_discarded == True)
+            and_(Photo.id.in_(photo_ids), Photo.is_discarded == True, Photo.user_id == current_user.id)
         )
     )
     photos = result.scalars().all()
diff --git a/backend/app/routers/folders.py b/backend/app/routers/folders.py
index 29dc2e8..81fcb8b 100644
--- a/backend/app/routers/folders.py
+++ b/backend/app/routers/folders.py
@@ -16,6 +16,8 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.database import get_db
 from app.models import Folder, SourceRoot, Photo
+from app.models.user import User
+from app.dependencies import get_current_user, get_user_folder
 
 logger = logging.getLogger(__name__)
 
@@ -48,10 +50,10 @@ def _validate_folder_name(name: str) -> str:
     return name
 
 @router.get("")
-async def get_folders(db: AsyncSession = Depends(get_db)):
+async def get_folders(db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Get all source folders"""
     # Get source roots instead of regular folders
-    result = await db.execute(select(SourceRoot).where(SourceRoot.is_active == True))
+    result = await db.execute(select(SourceRoot).where(SourceRoot.is_active == True, SourceRoot.user_id == current_user.id))
     source_roots = result.scalars().all()
     
     folders_list = []
@@ -73,7 +75,7 @@ async def get_folders(db: AsyncSession = Depends(get_db)):
     return {"folders": folders_list}
 
 @router.get("/tree")
-async def get_folder_tree(db: AsyncSession = Depends(get_db)):
+async def get_folder_tree(db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Recursive folder tree, one root per active SourceRoot. The tree
     starts at the Folder row matching the SourceRoot.path (the scanner
     creates one for every walked directory), with the SourceRoot's
@@ -97,7 +99,7 @@ async def get_folder_tree(db: AsyncSession = Depends(get_db)):
     creates as a parent walk) are skipped via path-prefix filtering.
     """
     sr_result = await db.execute(
-        select(SourceRoot).where(SourceRoot.is_active == True)  # noqa: E712
+        select(SourceRoot).where(SourceRoot.is_active == True, SourceRoot.user_id == current_user.id)  # noqa: E712
     )
     source_roots = sr_result.scalars().all()
 
@@ -196,6 +198,7 @@ async def rename_folder(
     folder_id: str,
     body: FolderRename,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Rename a folder. Two cases:
 
@@ -212,7 +215,7 @@ async def rename_folder(
 
     # Try SourceRoot first (display-only rename).
     sr_result = await db.execute(
-        select(SourceRoot).where(SourceRoot.id == folder_id)
+        select(SourceRoot).where(SourceRoot.id == folder_id, SourceRoot.user_id == current_user.id)
     )
     source_root = sr_result.scalar_one_or_none()
     if source_root:
@@ -225,14 +228,11 @@ async def rename_folder(
         }
 
     # Otherwise it's a Folder row.
-    folder_result = await db.execute(select(Folder).where(Folder.id == folder_id))
-    folder = folder_result.scalar_one_or_none()
-    if not folder:
-        raise HTTPException(status_code=404, detail="Folder not found")
+    folder = await get_user_folder(folder_id, current_user, db)
 
     # Refuse to rename the bare source root mount through here.
     sr_check = await db.execute(
-        select(SourceRoot).where(SourceRoot.id == folder.source_root_id)
+        select(SourceRoot).where(SourceRoot.id == folder.source_root_id, SourceRoot.user_id == current_user.id)
     )
     sr = sr_check.scalar_one_or_none()
     if sr and os.path.normpath(folder.path) == os.path.normpath(sr.path):
@@ -291,7 +291,7 @@ async def rename_folder(
 
 
 @router.post("", status_code=201)
-async def create_folder(body: FolderCreate, db: AsyncSession = Depends(get_db)):
+async def create_folder(body: FolderCreate, db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Create a new sub-folder under an existing Folder. Mirrors the
     create to disk so the next scan sees it. Body: { name, parent_id }.
     parent_id MUST be an existing Folder row id (any descendant of a
@@ -300,12 +300,7 @@ async def create_folder(body: FolderCreate, db: AsyncSession = Depends(get_db)):
     """
     name = _validate_folder_name(body.name)
 
-    parent_result = await db.execute(
-        select(Folder).where(Folder.id == body.parent_id)
-    )
-    parent = parent_result.scalar_one_or_none()
-    if not parent:
-        raise HTTPException(status_code=404, detail="Parent folder not found")
+    parent = await get_user_folder(body.parent_id, current_user, db)
 
     new_path = os.path.join(parent.path, name)
     if os.path.exists(new_path):
@@ -323,6 +318,7 @@ async def create_folder(body: FolderCreate, db: AsyncSession = Depends(get_db)):
         name=name,
         path=new_path,
         source_root_id=parent.source_root_id,
+        user_id=current_user.id,
         photo_count=0,
     )
     db.add(new_folder)
@@ -341,6 +337,7 @@ async def delete_folder(
     folder_id: str,
     mode: Literal['discard', 'permanent'] = Query('discard'),
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Delete a folder. Behavior depends on mode:
 
@@ -357,13 +354,10 @@ async def delete_folder(
     Refuses to delete the bare source-root mount in either mode (deleting
     the docker mount through the UI would be a footgun).
     """
-    folder_result = await db.execute(select(Folder).where(Folder.id == folder_id))
-    folder = folder_result.scalar_one_or_none()
-    if not folder:
-        raise HTTPException(status_code=404, detail="Folder not found")
+    folder = await get_user_folder(folder_id, current_user, db)
 
     sr_check = await db.execute(
-        select(SourceRoot).where(SourceRoot.id == folder.source_root_id)
+        select(SourceRoot).where(SourceRoot.id == folder.source_root_id, SourceRoot.user_id == current_user.id)
     )
     sr = sr_check.scalar_one_or_none()
     if sr and os.path.normpath(folder.path) == os.path.normpath(sr.path):
@@ -484,6 +478,7 @@ async def set_folder_hidden(
     folder_id: str,
     body: FolderHide,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Toggle the "hide from views" flag on a folder or source root.
 
@@ -502,7 +497,7 @@ async def set_folder_hidden(
     """
     # SourceRoot path — resolve to the Folder row at the mount point.
     sr_result = await db.execute(
-        select(SourceRoot).where(SourceRoot.id == folder_id)
+        select(SourceRoot).where(SourceRoot.id == folder_id, SourceRoot.user_id == current_user.id)
     )
     source_root = sr_result.scalar_one_or_none()
 
@@ -511,6 +506,7 @@ async def set_folder_hidden(
         root_folder_result = await db.execute(
             select(Folder).where(
                 Folder.source_root_id == source_root.id,
+                Folder.user_id == current_user.id,
                 Folder.path == os.path.normpath(source_root.path),
             )
         )
@@ -521,12 +517,7 @@ async def set_folder_hidden(
                 detail="Source root has no indexed Folder row yet; scan first.",
             )
     else:
-        folder_result = await db.execute(
-            select(Folder).where(Folder.id == folder_id)
-        )
-        folder = folder_result.scalar_one_or_none()
-        if folder is None:
-            raise HTTPException(status_code=404, detail="Folder not found")
+        folder = await get_user_folder(folder_id, current_user, db)
 
     folder.is_hidden = bool(body.hidden)
     await db.flush()
@@ -547,11 +538,11 @@ async def set_folder_hidden(
 
 
 @router.post("/{folder_id}/scan")
-async def scan_folder(folder_id: str, db: AsyncSession = Depends(get_db)):
+async def scan_folder(folder_id: str, db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Trigger manual re-scan of source root folder"""
     from app.tasks.celery import celery_app
-    
-    result = await db.execute(select(SourceRoot).where(SourceRoot.id == folder_id))
+
+    result = await db.execute(select(SourceRoot).where(SourceRoot.id == folder_id, SourceRoot.user_id == current_user.id))
     source_root = result.scalar_one_or_none()
     
     if not source_root:
diff --git a/backend/app/routers/heaps.py b/backend/app/routers/heaps.py
index 142221a..ccd72ef 100644
--- a/backend/app/routers/heaps.py
+++ b/backend/app/routers/heaps.py
@@ -14,6 +14,8 @@ from app.database import get_db
 from app.models import Heap, Photo, Folder
 from app.models.folders import SourceRoot
 from app.models.heaps import heap_photos
+from app.models.user import User
+from app.dependencies import get_current_user, get_user_heap
 
 logger = logging.getLogger(__name__)
 
@@ -48,7 +50,10 @@ class HeapConvertBody(BaseModel):
 # ── Endpoints ─────────────────────────────────────────────────────────────
 
 @router.get("")
-async def list_heaps(db: AsyncSession = Depends(get_db)):
+async def list_heaps(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+):
     """List all heaps with photo counts."""
     # LEFT JOIN heap_photos and group so we can return counts in one query.
     count_subq = (
@@ -63,6 +68,7 @@ async def list_heaps(db: AsyncSession = Depends(get_db)):
     stmt = (
         select(Heap, count_subq.c.photo_count)
         .outerjoin(count_subq, Heap.id == count_subq.c.heap_id)
+        .where(Heap.user_id == current_user.id)
         .order_by(Heap.created_at.asc())
     )
     result = await db.execute(stmt)
@@ -82,12 +88,16 @@ async def list_heaps(db: AsyncSession = Depends(get_db)):
 
 
 @router.post("", status_code=201)
-async def create_heap(body: HeapCreate, db: AsyncSession = Depends(get_db)):
+async def create_heap(
+    body: HeapCreate,
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+):
     """Create a new heap."""
     name = (body.name or "").strip()
     if not name:
         raise HTTPException(status_code=400, detail="Heap name is required")
-    heap = Heap(name=name)
+    heap = Heap(name=name, user_id=current_user.id)
     db.add(heap)
     await db.commit()
     await db.refresh(heap)
@@ -103,14 +113,14 @@ async def create_heap(body: HeapCreate, db: AsyncSession = Depends(get_db)):
 
 @router.patch("/{heap_id}")
 async def update_heap(
-    heap_id: str, body: HeapUpdate, db: AsyncSession = Depends(get_db)
+    heap_id: str,
+    body: HeapUpdate,
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Rename a heap and/or toggle active state. Setting is_active=true on
     one heap deactivates all others (single-active invariant)."""
-    result = await db.execute(select(Heap).where(Heap.id == heap_id))
-    heap = result.scalar_one_or_none()
-    if not heap:
-        raise HTTPException(status_code=404, detail="Heap not found")
+    heap = await get_user_heap(heap_id, current_user, db)
 
     if body.name is not None:
         name = body.name.strip()
@@ -120,8 +130,12 @@ async def update_heap(
 
     if body.is_active is not None:
         if body.is_active:
-            # Clear active flag on all other heaps in one statement
-            await db.execute(update(Heap).values(is_active=False))
+            # Clear active flag on all other heaps for this user
+            await db.execute(
+                update(Heap)
+                .where(Heap.user_id == current_user.id)
+                .values(is_active=False)
+            )
             heap.is_active = True
         else:
             heap.is_active = False
@@ -138,17 +152,18 @@ async def update_heap(
 
 
 @router.post("/{heap_id}/duplicate", status_code=201)
-async def duplicate_heap(heap_id: str, db: AsyncSession = Depends(get_db)):
+async def duplicate_heap(
+    heap_id: str,
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+):
     """Create a new heap with the same membership as an existing one. The
     new heap is named "{original} (copy)" and is never the active target —
     duplicating shouldn't quietly steal the user's T-key destination.
     """
-    result = await db.execute(select(Heap).where(Heap.id == heap_id))
-    source = result.scalar_one_or_none()
-    if not source:
-        raise HTTPException(status_code=404, detail="Heap not found")
+    source = await get_user_heap(heap_id, current_user, db)
 
-    new_heap = Heap(name=f"{source.name} (copy)", is_active=False)
+    new_heap = Heap(name=f"{source.name} (copy)", is_active=False, user_id=current_user.id)
     db.add(new_heap)
     await db.flush()  # populate new_heap.id without committing yet
 
@@ -178,24 +193,30 @@ async def duplicate_heap(heap_id: str, db: AsyncSession = Depends(get_db)):
 
 
 @router.delete("/{heap_id}", status_code=204)
-async def delete_heap(heap_id: str, db: AsyncSession = Depends(get_db)):
+async def delete_heap(
+    heap_id: str,
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+):
     """Delete a heap. Photos themselves are unaffected — only the membership
     rows in heap_photos cascade-delete."""
-    result = await db.execute(select(Heap).where(Heap.id == heap_id))
-    heap = result.scalar_one_or_none()
-    if not heap:
-        raise HTTPException(status_code=404, detail="Heap not found")
+    heap = await get_user_heap(heap_id, current_user, db)
     await db.delete(heap)
     await db.commit()
     return None
 
 
 @router.get("/{heap_id}/photo_ids")
-async def get_heap_photo_ids(heap_id: str, db: AsyncSession = Depends(get_db)):
+async def get_heap_photo_ids(
+    heap_id: str,
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+):
     """Return just the photo ids belonging to a heap. Used by the frontend
     to maintain a fast client-side membership lookup for the active heap
     (for the basket affordance on thumbnails) without fetching full photo
     records."""
+    await get_user_heap(heap_id, current_user, db)
     result = await db.execute(
         select(heap_photos.c.photo_id).where(heap_photos.c.heap_id == heap_id)
     )
@@ -204,14 +225,14 @@ async def get_heap_photo_ids(heap_id: str, db: AsyncSession = Depends(get_db)):
 
 @router.post("/{heap_id}/photos")
 async def add_photos_to_heap(
-    heap_id: str, body: HeapPhotosBody, db: AsyncSession = Depends(get_db)
+    heap_id: str,
+    body: HeapPhotosBody,
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Add photos to a heap. Idempotent: re-adding existing members is a
     no-op (handled by an INSERT OR IGNORE-style filter on duplicates)."""
-    result = await db.execute(select(Heap).where(Heap.id == heap_id))
-    heap = result.scalar_one_or_none()
-    if not heap:
-        raise HTTPException(status_code=404, detail="Heap not found")
+    await get_user_heap(heap_id, current_user, db)
 
     if not body.photo_ids:
         return {"status": "success", "added": 0}
@@ -241,6 +262,7 @@ async def convert_heap_to_folder(
     heap_id: str,
     body: HeapConvertBody,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Convert a heap into a folder by moving (or copying) every member
     photo into the target directory. Optionally deletes the heap row at
@@ -249,10 +271,7 @@ async def convert_heap_to_folder(
     target_id may be a Folder id or a SourceRoot id (matches the
     /photos/move convention so the same dropdown can populate it).
     """
-    heap_result = await db.execute(select(Heap).where(Heap.id == heap_id))
-    heap = heap_result.scalar_one_or_none()
-    if not heap:
-        raise HTTPException(status_code=404, detail="Heap not found")
+    heap = await get_user_heap(heap_id, current_user, db)
 
     # Resolve target_id → (target_dir, target_folder)
     sr_check = await db.execute(
@@ -402,13 +421,13 @@ async def convert_heap_to_folder(
 
 @router.delete("/{heap_id}/photos")
 async def remove_photos_from_heap(
-    heap_id: str, body: HeapPhotosBody, db: AsyncSession = Depends(get_db)
+    heap_id: str,
+    body: HeapPhotosBody,
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Remove photos from a heap. Removing a non-member is a no-op."""
-    result = await db.execute(select(Heap).where(Heap.id == heap_id))
-    heap = result.scalar_one_or_none()
-    if not heap:
-        raise HTTPException(status_code=404, detail="Heap not found")
+    await get_user_heap(heap_id, current_user, db)
 
     if not body.photo_ids:
         return {"status": "success", "removed": 0}
diff --git a/backend/app/routers/library.py b/backend/app/routers/library.py
index 286437d..68c1c49 100644
--- a/backend/app/routers/library.py
+++ b/backend/app/routers/library.py
@@ -11,42 +11,42 @@ import os
 import shutil
 from typing import List, Optional
 
-from fastapi import APIRouter, Depends
+from fastapi import APIRouter, Depends, Query
 from pydantic import BaseModel, Field
-from sqlalchemy import select, func, update
+from sqlalchemy import select, func, update, true as sa_true
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.database import get_db
 from app.models import Photo
+from app.models.user import User
+from app.dependencies import get_current_user
 
 logger = logging.getLogger(__name__)
 
 router = APIRouter()
 
+
+def _owner_filter(user: User, scope: str | None):
+    """Return a column expression scoping photos to the current user,
+    or a pass-through true() when an admin requests global scope."""
+    if scope == "global" and user.role == "admin":
+        return sa_true()
+    return Photo.user_id == user.id
+
 # Media types we accept in the regenerate-thumbnails request body. Mirrors
 # the values produced by `app.tasks.scan.get_media_type`.
 _VALID_MEDIA_TYPES = {'photo', 'raw', 'heic', 'video'}
 
 @router.get("/stats")
-async def get_library_stats(db: AsyncSession = Depends(get_db)):
-    """Get library statistics + per-section counts. Each section count
-    matches the filter the sidebar applies when you click it, so the
-    sidebar badges and the timeline below them stay in sync.
-
-      - all_photos:   non-discarded photos + videos (matches the All
-                      Photos section's default filter)
-      - rated:        non-discarded with rating >= 1
-      - colored:      non-discarded with a color_label set (matches the
-                      Colors grouped view's labeled buckets)
-      - duplicates:   non-discarded with is_duplicate = true
-      - discarded:    is_discarded = true
-      - total_size:   raw bytes across every row, including discarded
-    """
-    # Every sidebar badge runs against this filter. `not_visible` is the
-    # inverse: a photo is visible iff it's neither discarded nor hidden
-    # (marked hidden-from-views via a folder toggle). Kept as a single
-    # expression so every sub-count below applies it identically.
-    visible = (Photo.is_discarded.is_(False)) & (Photo.is_hidden.is_(False))
+async def get_library_stats(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    scope: str | None = Query(None),
+):
+    """Get library statistics. Pass ?scope=global (admin only) for
+    cross-user totals (used by the Settings page)."""
+    owner = _owner_filter(current_user, scope)
+    visible = owner & (Photo.is_discarded.is_(False)) & (Photo.is_hidden.is_(False))
 
     all_photos_count = (
         await db.execute(select(func.count(Photo.id)).where(visible))
@@ -84,7 +84,7 @@ async def get_library_stats(db: AsyncSession = Depends(get_db)):
 
     discarded_count = (
         await db.execute(
-            select(func.count(Photo.id)).where(Photo.is_discarded.is_(True))
+            select(func.count(Photo.id)).where(owner, Photo.is_discarded.is_(True))
         )
     ).scalar() or 0
 
@@ -92,17 +92,18 @@ async def get_library_stats(db: AsyncSession = Depends(get_db)):
     photo_count = (
         await db.execute(
             select(func.count(Photo.id)).where(
+                owner,
                 Photo.media_type.in_(['photo', 'heic', 'raw'])
             )
         )
     ).scalar() or 0
     video_count = (
         await db.execute(
-            select(func.count(Photo.id)).where(Photo.media_type == 'video')
+            select(func.count(Photo.id)).where(owner, Photo.media_type == 'video')
         )
     ).scalar() or 0
 
-    size = (await db.execute(select(func.sum(Photo.file_size)))).scalar() or 0
+    size = (await db.execute(select(func.sum(Photo.file_size)).where(owner))).scalar() or 0
 
     return {
         "all_photos": all_photos_count,
@@ -118,7 +119,7 @@ async def get_library_stats(db: AsyncSession = Depends(get_db)):
     }
 
 @router.post("/scan")
-async def trigger_scan():
+async def trigger_scan(current_user: User = Depends(get_current_user)):
     """Trigger full library re-scan"""
     from app.tasks.scan import scan_all_source_roots
 
@@ -128,7 +129,7 @@ async def trigger_scan():
 
 
 @router.post("/backfill-gps")
-async def trigger_backfill_gps():
+async def trigger_backfill_gps(current_user: User = Depends(get_current_user)):
     """Re-run EXIF metadata extraction on every photo that's still missing
     GPS coordinates. Useful after fixing the EXIF parser, or any time the
     Map view looks emptier than expected. Returns immediately — work runs
@@ -139,7 +140,7 @@ async def trigger_backfill_gps():
     return {"status": "success", "message": "GPS backfill queued"}
 
 @router.get("/scan/status")
-async def get_scan_status(db: AsyncSession = Depends(get_db)):
+async def get_scan_status(db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Get current scan status"""
     import redis
     from app.config import settings
@@ -187,20 +188,27 @@ class RegenerateThumbnailsRequest(BaseModel):
 
 
 @router.get("/maintenance/thumbnail-stats")
-async def get_thumbnail_stats(db: AsyncSession = Depends(get_db)):
+async def get_thumbnail_stats(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    scope: str | None = Query(None),
+):
     """Counts of photos by processing_status, plus a media-type breakdown
     so the Settings panel can show the user what's outstanding."""
+    owner = _owner_filter(current_user, scope)
     status_rows = (
         await db.execute(
-            select(Photo.processing_status, func.count(Photo.id)).group_by(
-                Photo.processing_status
-            )
+            select(Photo.processing_status, func.count(Photo.id))
+            .where(owner)
+            .group_by(Photo.processing_status)
         )
     ).all()
 
     media_rows = (
         await db.execute(
-            select(Photo.media_type, func.count(Photo.id)).group_by(Photo.media_type)
+            select(Photo.media_type, func.count(Photo.id))
+            .where(owner)
+            .group_by(Photo.media_type)
         )
     ).all()
 
@@ -222,6 +230,8 @@ async def get_thumbnail_stats(db: AsyncSession = Depends(get_db)):
 async def regenerate_thumbnails(
     body: RegenerateThumbnailsRequest,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    scope: str | None = Query(None),
 ):
     """Reset matching photos' on-disk thumbnail directories and re-queue
     Celery thumbnail generation. Used by the Settings panel for the
@@ -233,6 +243,8 @@ async def regenerate_thumbnails(
     """
     from app.tasks.thumbs import generate_thumbnails
 
+    owner = _owner_filter(current_user, scope)
+
     # Validate media_types early so a typo can't silently match nothing.
     media_types = body.media_types
     if media_types is not None:
@@ -244,7 +256,7 @@ async def regenerate_thumbnails(
                            f"Allowed: {sorted(_VALID_MEDIA_TYPES)}",
             }
 
-    query = select(Photo)
+    query = select(Photo).where(owner)
     if media_types:
         query = query.where(Photo.media_type.in_(media_types))
     if body.only_failed:
@@ -297,7 +309,11 @@ async def regenerate_thumbnails(
 
 
 @router.get("/maintenance/worker-status")
-async def get_worker_status(db: AsyncSession = Depends(get_db)):
+async def get_worker_status(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    scope: str | None = Query(None),
+):
     """Diagnostics for the Celery worker fleet + recent task failures.
 
     Surfaced in the Settings panel so the user can spot a stuck queue or
@@ -316,6 +332,7 @@ async def get_worker_status(db: AsyncSession = Depends(get_db)):
         things failed without opening the DB.
       - broker_ok: bool — could we even reach Redis?
     """
+    owner = _owner_filter(current_user, scope)
     from app.tasks.celery import celery_app
     from app.config import settings
     import redis as _redis
@@ -398,7 +415,7 @@ async def get_worker_status(db: AsyncSession = Depends(get_db)):
     # ----- Recent task failures from the photos table ----------------------
     failed_total = (
         await db.execute(
-            select(func.count(Photo.id)).where(Photo.processing_status == 'failed')
+            select(func.count(Photo.id)).where(owner, Photo.processing_status == 'failed')
         )
     ).scalar() or 0
 
@@ -411,7 +428,7 @@ async def get_worker_status(db: AsyncSession = Depends(get_db)):
                 Photo.processing_error,
                 Photo.updated_at,
             )
-            .where(Photo.processing_status == 'failed')
+            .where(owner, Photo.processing_status == 'failed')
             .order_by(Photo.updated_at.desc().nullslast())
             .limit(20)
         )
@@ -454,7 +471,11 @@ async def get_worker_status(db: AsyncSession = Depends(get_db)):
 
 
 @router.get("/maintenance/pipeline-stats")
-async def get_pipeline_stats(db: AsyncSession = Depends(get_db)):
+async def get_pipeline_stats(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    scope: str | None = Query(None),
+):
     """Per-stage progress across the ingestion pipeline.
 
     Returns a `{stage_key: {done, total, label}}` map so the Settings
@@ -470,7 +491,8 @@ async def get_pipeline_stats(db: AsyncSession = Depends(get_db)):
     from app.models import Embedding, FaceEmbedding, OCRText
     from app.models.tags import photo_tags  # association Table, not a model
 
-    not_discarded = Photo.is_discarded.is_(False)
+    owner = _owner_filter(current_user, scope)
+    not_discarded = owner & Photo.is_discarded.is_(False)
 
     async def scalar_count(query):
         return (await db.execute(query)).scalar() or 0
@@ -654,7 +676,7 @@ async def get_pipeline_stats(db: AsyncSession = Depends(get_db)):
 
 
 @router.get("/maintenance/missing-stats")
-async def get_missing_stats():
+async def get_missing_stats(current_user: User = Depends(get_current_user)):
     """Count photos whose files no longer exist on disk under a mounted
     source root. Surfaced in Settings so the user can see a number before
     pulling the trigger on prune-missing. Cheap enough to call freely."""
@@ -663,7 +685,7 @@ async def get_missing_stats():
 
 
 @router.post("/maintenance/prune-missing")
-async def run_prune_missing():
+async def run_prune_missing(current_user: User = Depends(get_current_user)):
     """Actually delete the orphaned photo rows reported by /missing-stats.
     Common cause: PHOTO_DIRS in .env was repointed at a different library
     leaving every old row dangling. Skips any photo whose source root
@@ -677,7 +699,7 @@ async def run_prune_missing():
 
 
 @router.post("/maintenance/cleanup")
-async def run_data_integrity_cleanup():
+async def run_data_integrity_cleanup(current_user: User = Depends(get_current_user)):
     """Re-run the source-roots / folders / photos data-integrity cleanup
     that normally only runs on backend startup. Idempotent."""
     from app.services.cleanup import cleanup_data_integrity
@@ -695,7 +717,11 @@ async def run_data_integrity_cleanup():
 # ─────────────────────────────────────────────────────────────────────────
 
 @router.get("/duplicates/groups")
-async def get_duplicate_groups(db: AsyncSession = Depends(get_db)):
+async def get_duplicate_groups(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+    scope: str | None = Query(None),
+):
     """Return every duplicate group with its members.
 
     Drives the frontend grouped grid view in the Duplicates section. One
@@ -708,6 +734,7 @@ async def get_duplicate_groups(db: AsyncSession = Depends(get_db)):
                     duplicates that the perceptual hash trivially caught)
       * "similar" — members differ at the byte level but match perceptually
     """
+    owner = _owner_filter(current_user, scope)
     rows = (
         await db.execute(
             select(
@@ -723,6 +750,7 @@ async def get_duplicate_groups(db: AsyncSession = Depends(get_db)):
                 Photo.media_type,
                 Photo.duplicate_group_id,
             )
+            .where(owner)
             .where(Photo.duplicate_group_id.is_not(None))
             .where(Photo.is_discarded.is_(False))
             .where(Photo.is_hidden.is_(False))
@@ -784,7 +812,7 @@ async def get_duplicate_groups(db: AsyncSession = Depends(get_db)):
 
 
 @router.post("/maintenance/regroup-duplicates")
-async def trigger_regroup_duplicates():
+async def trigger_regroup_duplicates(current_user: User = Depends(get_current_user)):
     """Recompute duplicate groups from current perceptual hashes.
 
     Fires the celery `regroup_duplicates` task which walks every photo's
@@ -800,7 +828,7 @@ async def trigger_regroup_duplicates():
 
 
 @router.post("/maintenance/backfill-phashes")
-async def trigger_backfill_phashes():
+async def trigger_backfill_phashes(current_user: User = Depends(get_current_user)):
     """Compute perceptual hashes for every photo currently missing one.
 
     One-shot recovery path for libraries that existed before the phash
diff --git a/backend/app/routers/photos.py b/backend/app/routers/photos.py
index 2a63256..282538d 100644
--- a/backend/app/routers/photos.py
+++ b/backend/app/routers/photos.py
@@ -7,9 +7,10 @@ from pathlib import Path
 from fastapi import APIRouter, Depends, HTTPException, Query, Response
 from fastapi.responses import FileResponse
 from pydantic import BaseModel
-from sqlalchemy import select, and_, or_, func
+from sqlalchemy import select, and_, or_, func, tuple_
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload
+import base64
 import json
 import os
 import logging
@@ -19,11 +20,13 @@ logger = logging.getLogger(__name__)
 from app.database import get_db
 from app.models import Photo, Folder, Tag
 from app.models.folders import SourceRoot
+from app.models.user import User
 from app.models.heaps import heap_photos
 from app.models.tags import photo_tags
 from app.schemas.photos import PhotoResponse, PhotoUpdate, PhotoListResponse, BulkAction
 from app.services.exif_writer import ExifWriteError, write_taken_at
 from app.services.date_guess import has_date_warning as compute_date_warning
+from app.dependencies import get_current_user, get_user_photo
 from app.config import settings
 
 router = APIRouter()
@@ -47,13 +50,15 @@ async def list_photos(
     order: str = "desc",
     page: int = Query(1, ge=1),
     per_page: int = Query(100, ge=1, le=500),
-    db: AsyncSession = Depends(get_db)
+    cursor: Optional[str] = Query(None, description="Opaque cursor for keyset pagination"),
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """List photos with filters and pagination"""
-    
+
     # Build query — eager-load tags so the response can include them
-    # without an N+1 round-trip per photo.
-    query = select(Photo).options(selectinload(Photo.tags))
+    # without an N+1 round-trip per photo. Scoped to the current user.
+    query = select(Photo).options(selectinload(Photo.tags)).where(Photo.user_id == current_user.id)
     
     # Apply filters
     filters = []
@@ -206,24 +211,92 @@ async def list_photos(
         "rating": Photo.rating,
     }
     sort_column = SORT_WHITELIST.get(sort, Photo.taken_at)
-    if order == "desc":
-        query = query.order_by(sort_column.desc())
+    desc = order == "desc"
+
+    # Keyset / cursor pagination — O(1) regardless of page depth.
+    # The cursor encodes the last-seen (sort_value, id) pair so the DB
+    # can seek directly to the next slice via an indexed range scan
+    # instead of skipping N rows with OFFSET.
+    if cursor:
+        try:
+            decoded = json.loads(base64.urlsafe_b64decode(cursor))
+            cursor_val = decoded["v"]
+            cursor_id = decoded["id"]
+            # For datetime columns, parse the ISO string back.
+            if sort in ("taken_at", "added_at") and cursor_val is not None:
+                cursor_val = datetime.fromisoformat(cursor_val)
+        except Exception:
+            raise HTTPException(status_code=400, detail="Invalid cursor")
+
+        # Keyset condition: for DESC we want rows "less than" the cursor,
+        # for ASC rows "greater than". We use (sort_col, id) tuple
+        # comparison which handles NULLs and ties correctly.
+        if desc:
+            if cursor_val is None:
+                # NULL sorts last in DESC with NULLS LAST — seek past it by id
+                query = query.where(
+                    or_(
+                        sort_column.is_(None) & (Photo.id < cursor_id),
+                    )
+                )
+            else:
+                query = query.where(
+                    or_(
+                        sort_column < cursor_val,
+                        and_(sort_column == cursor_val, Photo.id < cursor_id),
+                        sort_column.is_(None),
+                    )
+                )
+        else:
+            if cursor_val is None:
+                query = query.where(
+                    or_(
+                        sort_column.is_(None) & (Photo.id > cursor_id),
+                    )
+                )
+            else:
+                query = query.where(
+                    or_(
+                        sort_column > cursor_val,
+                        and_(sort_column == cursor_val, Photo.id > cursor_id),
+                    )
+                )
+
+    if desc:
+        query = query.order_by(sort_column.desc().nulls_last(), Photo.id.desc())
     else:
-        query = query.order_by(sort_column.asc())
-    
-    # Count total results
-    count_query = select(func.count()).select_from(query.subquery())
-    total_result = await db.execute(count_query)
-    total = total_result.scalar()
-    
-    # Apply pagination
-    offset = (page - 1) * per_page
-    query = query.offset(offset).limit(per_page)
-    
+        query = query.order_by(sort_column.asc().nulls_last(), Photo.id.asc())
+
+    # Count total results (only when no cursor — first page needs it;
+    # subsequent pages reuse the total from the first response).
+    total = None
+    if not cursor:
+        count_query = select(func.count()).select_from(query.subquery())
+        total_result = await db.execute(count_query)
+        total = total_result.scalar()
+
+    # Fallback to offset pagination when no cursor is provided and page > 1
+    # (backward compat for any callers not yet using cursors).
+    if not cursor and page > 1:
+        offset = (page - 1) * per_page
+        query = query.offset(offset)
+
+    query = query.limit(per_page)
+
     # Execute query
     result = await db.execute(query)
     photos = result.scalars().all()
-    
+
+    # Build next_cursor from the last row in this batch.
+    next_cursor = None
+    if photos and len(photos) == per_page:
+        last = photos[-1]
+        sort_val = getattr(last, sort if sort in SORT_WHITELIST else "taken_at")
+        if isinstance(sort_val, datetime):
+            sort_val = sort_val.isoformat()
+        cursor_payload = json.dumps({"v": sort_val, "id": last.id})
+        next_cursor = base64.urlsafe_b64encode(cursor_payload.encode()).decode()
+
     # Convert to response, attaching tags inline so the frontend can group
     # client-side without a second round-trip.
     photo_dicts = []
@@ -235,21 +308,25 @@ async def list_photos(
         ]
         photo_dicts.append(d)
 
-    return {
+    response = {
         "photos": photo_dicts,
-        "total": total,
-        "page": page,
         "per_page": per_page,
-        "pages": (total + per_page - 1) // per_page if total else 0,
+        "next_cursor": next_cursor,
     }
+    # Include total + legacy page fields on first page / non-cursor requests
+    if total is not None:
+        response["total"] = total
+        response["page"] = page
+        response["pages"] = (total + per_page - 1) // per_page if total else 0
+    return response
 
 @router.get("/map")
-async def list_photos_with_gps(db: AsyncSession = Depends(get_db)):
+async def list_photos_with_gps(
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
+):
     """Lightweight listing of every non-discarded photo that has GPS
-    coordinates, used by the Map view. Intentionally returns a flat list
-    (no pagination) with only the fields the map renderer needs, so even
-    large libraries serialize to a few MB at most. Declared *before*
-    ``/{photo_id}`` so the literal path wins the FastAPI route match."""
+    coordinates, used by the Map view."""
     result = await db.execute(
         select(
             Photo.id,
@@ -257,6 +334,7 @@ async def list_photos_with_gps(db: AsyncSession = Depends(get_db)):
             Photo.longitude,
             Photo.taken_at,
         ).where(
+            Photo.user_id == current_user.id,
             Photo.is_discarded.is_(False),
             Photo.is_hidden.is_(False),
             Photo.latitude.is_not(None),
@@ -277,16 +355,11 @@ async def list_photos_with_gps(db: AsyncSession = Depends(get_db)):
 @router.get("/{photo_id}")
 async def get_photo(
     photo_id: str,
-    db: AsyncSession = Depends(get_db)
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Get single photo with full EXIF and its tags."""
-    result = await db.execute(
-        select(Photo).where(Photo.id == photo_id)
-    )
-    photo = result.scalar_one_or_none()
-
-    if not photo:
-        raise HTTPException(status_code=404, detail="Photo not found")
+    photo = await get_user_photo(photo_id, current_user, db)
 
     # Fetch tags via the join table so we don't need to declare a
     # relationship on the Photo model side.
@@ -310,12 +383,11 @@ async def add_photo_tags(
     photo_id: str,
     body: dict,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Add one or more tags to a photo. Body: { tag_ids: [str, ...] }.
     Idempotent: re-adding existing members is a no-op."""
-    photo_result = await db.execute(select(Photo).where(Photo.id == photo_id))
-    if photo_result.scalar_one_or_none() is None:
-        raise HTTPException(status_code=404, detail="Photo not found")
+    await get_user_photo(photo_id, current_user, db)
 
     tag_ids = body.get("tag_ids") or []
     if not isinstance(tag_ids, list) or not tag_ids:
@@ -346,8 +418,10 @@ async def remove_photo_tag(
     photo_id: str,
     tag_id: str,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Remove a tag from a photo. Removing a non-member is a no-op."""
+    await get_user_photo(photo_id, current_user, db)
     from sqlalchemy import delete as sql_delete
     await db.execute(
         sql_delete(photo_tags).where(
@@ -363,22 +437,21 @@ async def get_thumbnail(
     photo_id: str,
     size: str,
     response: Response,
-    db: AsyncSession = Depends(get_db)
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Serve thumbnail (with Nginx X-Accel-Redirect support)"""
     if size not in ['small', 'medium', 'large']:
         raise HTTPException(status_code=400, detail="Invalid thumbnail size")
-    
-    result = await db.execute(
-        select(Photo).where(Photo.id == photo_id)
-    )
-    photo = result.scalar_one_or_none()
-    
-    if not photo:
-        raise HTTPException(status_code=404, detail="Photo not found")
-    
-    # Check if thumbnail exists, generate if not
-    thumb_dir = f"/data/thumbs/{photo_id}"
+
+    photo = await get_user_photo(photo_id, current_user, db)
+
+    # Check if thumbnail exists, generate if not.
+    # User-prefixed path for isolation.
+    if photo.user_id:
+        thumb_dir = f"/data/thumbs/{photo.user_id}/{photo_id}"
+    else:
+        thumb_dir = f"/data/thumbs/{photo_id}"
     thumb_path = f"{thumb_dir}/{size}.webp"
     
     if not os.path.exists(thumb_path):
@@ -451,16 +524,11 @@ async def get_thumbnail(
 @router.get("/{photo_id}/original")
 async def get_original(
     photo_id: str,
-    db: AsyncSession = Depends(get_db)
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Serve original file (download for RAW, inline for web-safe formats)"""
-    result = await db.execute(
-        select(Photo).where(Photo.id == photo_id)
-    )
-    photo = result.scalar_one_or_none()
-
-    if not photo:
-        raise HTTPException(status_code=404, detail="Photo not found")
+    photo = await get_user_photo(photo_id, current_user, db)
 
     if not os.path.exists(photo.filepath):
         raise HTTPException(status_code=404, detail="File not found")
@@ -560,19 +628,10 @@ async def get_proxy(
     photo_id: str,
     response: Response,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
-    """Serve a full-resolution WebP proxy for non-web-safe formats (RAW, HEIC,
-    TIFF) so the loupe view can display them inline. Web-safe formats are
-    redirected to /original to avoid pointless transcoding.
-
-    Cached at /data/proxies/{photo_id}.webp; subsequent requests serve the
-    cached file (with optional X-Accel-Redirect for production).
-    """
-    result = await db.execute(select(Photo).where(Photo.id == photo_id))
-    photo = result.scalar_one_or_none()
-
-    if not photo:
-        raise HTTPException(status_code=404, detail="Photo not found")
+    """Serve a full-resolution WebP proxy for non-web-safe formats."""
+    photo = await get_user_photo(photo_id, current_user, db)
 
     if not os.path.exists(photo.filepath):
         raise HTTPException(status_code=404, detail="File not found")
@@ -613,19 +672,11 @@ async def get_proxy(
 async def update_photo(
     photo_id: str,
     update: PhotoUpdate,
-    db: AsyncSession = Depends(get_db)
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
-    """Update photo metadata. If `filename` is included, also rename the
-    file on disk in its current directory (no cross-folder moves through
-    this endpoint).
-    """
-    result = await db.execute(
-        select(Photo).where(Photo.id == photo_id)
-    )
-    photo = result.scalar_one_or_none()
-
-    if not photo:
-        raise HTTPException(status_code=404, detail="Photo not found")
+    """Update photo metadata."""
+    photo = await get_user_photo(photo_id, current_user, db)
 
     update_data = update.dict(exclude_unset=True)
 
@@ -692,19 +743,11 @@ async def update_photo(
 @router.delete("/{photo_id}")
 async def discard_photo(
     photo_id: str,
-    db: AsyncSession = Depends(get_db)
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
-    """Soft-discard a photo: sets is_discarded=true. The file stays on disk so
-    restore is just a flag flip. Permanent deletion happens via DELETE
-    /discard/{id} or DELETE /discard/empty.
-    """
-    result = await db.execute(
-        select(Photo).where(Photo.id == photo_id)
-    )
-    photo = result.scalar_one_or_none()
-
-    if not photo:
-        raise HTTPException(status_code=404, detail="Photo not found")
+    """Soft-discard a photo."""
+    photo = await get_user_photo(photo_id, current_user, db)
 
     photo.is_discarded = True
     photo.discarded_at = datetime.utcnow()
@@ -726,6 +769,7 @@ class CopyRequest(BaseModel):
 async def copy_photos(
     body: CopyRequest,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Copy photos into a target folder. Same target resolution as /move
     (folder id or source root id), but uses shutil.copy2 and creates new
@@ -767,7 +811,7 @@ async def copy_photos(
         return {"status": "success", "copied": 0, "errors": []}
 
     photos_result = await db.execute(
-        select(Photo).where(Photo.id.in_(body.photo_ids))
+        select(Photo).where(Photo.id.in_(body.photo_ids), Photo.user_id == current_user.id)
     )
     photos_to_copy = photos_result.scalars().all()
 
@@ -820,6 +864,7 @@ async def copy_photos(
             file_size=photo.file_size,
             taken_at=photo.taken_at,
             taken_at_source=photo.taken_at_source,
+            user_id=current_user.id,
             user_title=photo.user_title,
             user_notes=photo.user_notes,
             rating=photo.rating,
@@ -844,6 +889,7 @@ async def copy_photos(
 async def move_photos(
     body: MoveRequest,
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Move photos into a target folder. The target can be either a Folder
     id or a SourceRoot id (since the LeftSidebar only exposes source roots
@@ -887,9 +933,9 @@ async def move_photos(
     if not body.photo_ids:
         return {"status": "success", "moved": 0, "errors": []}
 
-    # Fetch the photo rows
+    # Fetch the photo rows, scoped to user
     photos_result = await db.execute(
-        select(Photo).where(Photo.id.in_(body.photo_ids))
+        select(Photo).where(Photo.id.in_(body.photo_ids), Photo.user_id == current_user.id)
     )
     photos_to_move = photos_result.scalars().all()
 
@@ -932,12 +978,13 @@ async def move_photos(
 @router.post("/bulk")
 async def bulk_action(
     action: BulkAction,
-    db: AsyncSession = Depends(get_db)
+    db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Perform bulk actions on multiple photos"""
-    # Get photos
+    # Get photos, scoped to user
     result = await db.execute(
-        select(Photo).where(Photo.id.in_(action.ids))
+        select(Photo).where(Photo.id.in_(action.ids), Photo.user_id == current_user.id)
     )
     photos = result.scalars().all()
     
diff --git a/backend/app/routers/search.py b/backend/app/routers/search.py
index 3954fed..9d28d49 100644
--- a/backend/app/routers/search.py
+++ b/backend/app/routers/search.py
@@ -10,6 +10,8 @@ from sqlalchemy import select
 from app.database import get_db
 from app.models import Photo
 from app.services.search import hybrid_search
+from app.models.user import User
+from app.dependencies import get_current_user
 
 router = APIRouter()
 
@@ -22,7 +24,7 @@ class SearchRequest(BaseModel):
 
 
 @router.post("")
-async def search_photos(body: SearchRequest, db: AsyncSession = Depends(get_db)):
+async def search_photos(body: SearchRequest, db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Unified search endpoint. Every query runs hybrid (FTS + semantic)
     by default — the user never picks a mode.
 
@@ -47,7 +49,7 @@ async def search_photos(body: SearchRequest, db: AsyncSession = Depends(get_db))
 
     # Hydrate with photo data
     photo_ids = [r["photo_id"] for r in results]
-    stmt = select(Photo).where(Photo.id.in_(photo_ids))
+    stmt = select(Photo).where(Photo.id.in_(photo_ids), Photo.user_id == current_user.id)
     rows = (await db.execute(stmt)).scalars().all()
     photo_map = {p.id: p for p in rows}
 
diff --git a/backend/app/routers/tags.py b/backend/app/routers/tags.py
index 8ae8ba0..d10a90b 100644
--- a/backend/app/routers/tags.py
+++ b/backend/app/routers/tags.py
@@ -15,6 +15,8 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from app.database import get_db
 from app.models import Photo, Tag
 from app.models.tags import photo_tags
+from app.models.user import User
+from app.dependencies import get_current_user
 
 router = APIRouter()
 
@@ -42,6 +44,7 @@ class TagMerge(BaseModel):
 async def list_tags(
     kind: Optional[str] = Query(None, description="Filter by kind: user, object, scene, face_cluster"),
     db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """List all tags with their photo counts, optionally filtered by kind.
 
@@ -61,6 +64,7 @@ async def list_tags(
             photo_tags.join(Photo, Photo.id == photo_tags.c.photo_id)
         )
         .where(
+            Photo.user_id == current_user.id,
             Photo.is_discarded.is_(False),
             Photo.is_hidden.is_(False),
         )
@@ -70,6 +74,7 @@ async def list_tags(
     stmt = (
         select(Tag, count_subq.c.photo_count, count_subq.c.first_photo_id)
         .outerjoin(count_subq, Tag.id == count_subq.c.tag_id)
+        .where(Tag.user_id == current_user.id)
     )
     if kind:
         stmt = stmt.where(Tag.kind == kind)
@@ -93,7 +98,7 @@ async def list_tags(
 
 
 @router.post("", status_code=201)
-async def create_tag(body: TagCreate, db: AsyncSession = Depends(get_db)):
+async def create_tag(body: TagCreate, db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Create a new tag. The (name, kind) pair is unique — re-creating an
     existing pair returns the existing row (idempotent for autocomplete)."""
     name = (body.name or "").strip()
@@ -101,7 +106,7 @@ async def create_tag(body: TagCreate, db: AsyncSession = Depends(get_db)):
         raise HTTPException(status_code=400, detail="Tag name is required")
 
     existing = await db.execute(
-        select(Tag).where(Tag.name == name, Tag.kind == body.kind)
+        select(Tag).where(Tag.name == name, Tag.kind == body.kind, Tag.user_id == current_user.id)
     )
     found = existing.scalar_one_or_none()
     if found:
@@ -110,7 +115,7 @@ async def create_tag(body: TagCreate, db: AsyncSession = Depends(get_db)):
             "kind": found.kind, "photo_count": 0,
         }
 
-    tag = Tag(name=name, color=body.color, kind=body.kind)
+    tag = Tag(name=name, color=body.color, kind=body.kind, user_id=current_user.id)
     db.add(tag)
     await db.commit()
     await db.refresh(tag)
@@ -122,10 +127,11 @@ async def create_tag(body: TagCreate, db: AsyncSession = Depends(get_db)):
 
 @router.patch("/{tag_id}")
 async def update_tag(
-    tag_id: str, body: TagUpdate, db: AsyncSession = Depends(get_db)
+    tag_id: str, body: TagUpdate, db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Rename or recolor a tag (works for any kind — user, object, face_cluster)."""
-    result = await db.execute(select(Tag).where(Tag.id == tag_id))
+    result = await db.execute(select(Tag).where(Tag.id == tag_id, Tag.user_id == current_user.id))
     tag = result.scalar_one_or_none()
     if not tag:
         raise HTTPException(status_code=404, detail="Tag not found")
@@ -145,7 +151,8 @@ async def update_tag(
 
 @router.post("/{tag_id}/merge")
 async def merge_tag(
-    tag_id: str, body: TagMerge, db: AsyncSession = Depends(get_db)
+    tag_id: str, body: TagMerge, db: AsyncSession = Depends(get_db),
+    current_user: User = Depends(get_current_user),
 ):
     """Merge tag_id INTO target_id. All photo associations from the source
     tag are moved to the target, then the source tag is deleted.
@@ -155,8 +162,8 @@ async def merge_tag(
     if tag_id == body.target_id:
         raise HTTPException(status_code=400, detail="Cannot merge a tag into itself")
 
-    source = (await db.execute(select(Tag).where(Tag.id == tag_id))).scalar_one_or_none()
-    target = (await db.execute(select(Tag).where(Tag.id == body.target_id))).scalar_one_or_none()
+    source = (await db.execute(select(Tag).where(Tag.id == tag_id, Tag.user_id == current_user.id))).scalar_one_or_none()
+    target = (await db.execute(select(Tag).where(Tag.id == body.target_id, Tag.user_id == current_user.id))).scalar_one_or_none()
     if not source:
         raise HTTPException(status_code=404, detail="Source tag not found")
     if not target:
@@ -189,9 +196,9 @@ async def merge_tag(
 
 
 @router.delete("/{tag_id}", status_code=204)
-async def delete_tag(tag_id: str, db: AsyncSession = Depends(get_db)):
+async def delete_tag(tag_id: str, db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)):
     """Delete a tag. Photo associations cascade-delete via the FK."""
-    result = await db.execute(select(Tag).where(Tag.id == tag_id))
+    result = await db.execute(select(Tag).where(Tag.id == tag_id, Tag.user_id == current_user.id))
     tag = result.scalar_one_or_none()
     if not tag:
         raise HTTPException(status_code=404, detail="Tag not found")
diff --git a/backend/app/services/scanner.py b/backend/app/services/scanner.py
index 3aa9b07..6c3ccab 100644
--- a/backend/app/services/scanner.py
+++ b/backend/app/services/scanner.py
@@ -1,6 +1,5 @@
 """
-Scanner service for initial library scan and one-time bootstrap of the
-default source root on first boot.
+Scanner service for initial library scan and per-user source root bootstrap.
 """
 import os
 import logging
@@ -8,44 +7,74 @@ from sqlalchemy import select
 
 from app.database import AsyncSessionLocal
 from app.models import SourceRoot
+from app.models.user import User
 from app.tasks.scan import scan_all_source_roots
 from app.config import settings
 
 logger = logging.getLogger(__name__)
 
-# The single host → container mount path. The compose file mounts whatever
-# the user set as PHOTO_DIRS at this path.
-DEFAULT_LIBRARY_PATH = "/photos"
-DEFAULT_LIBRARY_NAME = "Library"
+
+async def bootstrap_user_source_root(user: User, session=None) -> None:
+    """Create the media directory and a source root for a user.
+
+    Called when a new user is created (by the admin or the setup endpoint).
+    If the user already has a source root, this is a no-op.
+    """
+    own_session = session is None
+    if own_session:
+        session = AsyncSessionLocal()
+
+    try:
+        # Check if user already has a source root
+        result = await session.execute(
+            select(SourceRoot).where(SourceRoot.user_id == user.id)
+        )
+        if result.scalar_one_or_none() is not None:
+            return
+
+        os.makedirs(user.media_path, exist_ok=True)
+
+        source_root = SourceRoot(
+            name=f"{user.username}'s Library",
+            path=user.media_path,
+            user_id=user.id,
+        )
+        session.add(source_root)
+        if own_session:
+            await session.commit()
+        else:
+            await session.flush()
+
+        logger.info(
+            f"Bootstrapped source root for user '{user.username}': "
+            f"{user.media_path}"
+        )
+    finally:
+        if own_session:
+            await session.close()
 
 
 async def bootstrap_default_source_root() -> None:
-    """If no source roots exist in the DB, create one pointing at the default
-    library mount. Lets a fresh install pick up photos with zero
-    configuration: the user only needs to set PHOTO_DIRS in .env.
+    """Legacy bootstrap — for existing installs that have source roots
+    without user_id (pre-auth migration). On fresh installs, source roots
+    are created per-user via bootstrap_user_source_root. If there are
+    already source roots in the DB, this is a no-op.
     """
-    if not os.path.isdir(DEFAULT_LIBRARY_PATH):
-        logger.warning(
-            f"Default library path {DEFAULT_LIBRARY_PATH} is not mounted; "
-            "set PHOTO_DIRS in .env and recreate the container."
-        )
-        return
-
     async with AsyncSessionLocal() as session:
         result = await session.execute(select(SourceRoot))
         if result.scalars().first() is not None:
-            return  # Already have at least one source root, leave it alone.
+            return  # Already have source roots.
 
-        source_root = SourceRoot(
-            name=DEFAULT_LIBRARY_NAME,
-            path=DEFAULT_LIBRARY_PATH,
-        )
-        session.add(source_root)
-        await session.commit()
-        logger.info(
-            f"Bootstrapped default source root: {DEFAULT_LIBRARY_NAME} → "
-            f"{DEFAULT_LIBRARY_PATH}"
-        )
+        # No source roots and no users means fresh install — the setup
+        # endpoint will create the first user + source root.
+        user_count = (await session.execute(
+            select(User)
+        )).scalars().first()
+        if user_count is None:
+            logger.info(
+                "No users or source roots — waiting for first-run setup."
+            )
+            return
 
 
 async def start_initial_scan():
diff --git a/backend/app/tasks/scan.py b/backend/app/tasks/scan.py
index 089cfd8..8f317aa 100644
--- a/backend/app/tasks/scan.py
+++ b/backend/app/tasks/scan.py
@@ -122,6 +122,13 @@ async def _scan_folder_async(folder_path: str, source_root_id: Optional[str], ta
             if not source_root_id:
                 source_root = await get_or_create_source_root(session, folder_path)
                 source_root_id = source_root.id
+            else:
+                source_root = (await session.execute(
+                    select(SourceRoot).where(SourceRoot.id == source_root_id)
+                )).scalar_one_or_none()
+
+            # Inherit user_id from the source root's owner
+            owner_user_id = source_root.user_id if source_root else None
 
             # Per-scan memoization cache for "is this folder's effective
             # is_hidden true?" Populated on first lookup by walking the
@@ -173,7 +180,7 @@ async def _scan_folder_async(folder_path: str, source_root_id: Optional[str], ta
 
             for root, dirs, files in os.walk(folder_path):
                 # Get or create folder entry
-                folder = await get_or_create_folder(session, root, source_root_id)
+                folder = await get_or_create_folder(session, root, source_root_id, owner_user_id)
                 progress_set(REDIS_KEY_CURRENT_FOLDER, root)
 
                 # Filter supported files
@@ -237,6 +244,7 @@ async def _scan_folder_async(folder_path: str, source_root_id: Optional[str], ta
                                 filepath=filepath,
                                 filename=filename,
                                 folder_id=folder.id,
+                                user_id=owner_user_id,
                                 file_hash=file_hash,
                                 media_type=get_media_type(filepath),
                                 original_format=Path(filepath).suffix.upper()[1:],
@@ -342,7 +350,9 @@ async def get_or_create_source_root(session: AsyncSession, path: str) -> SourceR
     return source_root
 
 
-async def get_or_create_folder(session: AsyncSession, path: str, source_root_id: str) -> Folder:
+async def get_or_create_folder(
+    session: AsyncSession, path: str, source_root_id: str, user_id: str = None
+) -> Folder:
     """Get or create a folder entry, matching by normalized path."""
     from sqlalchemy import select
 
@@ -364,7 +374,7 @@ async def get_or_create_folder(session: AsyncSession, path: str, source_root_id:
                 parent_id = parent.id
             else:
                 # Recursively create parent
-                parent = await get_or_create_folder(session, parent_path, source_root_id)
+                parent = await get_or_create_folder(session, parent_path, source_root_id, user_id)
                 parent_id = parent.id
         else:
             parent_id = None
@@ -374,6 +384,7 @@ async def get_or_create_folder(session: AsyncSession, path: str, source_root_id:
             path=norm,
             parent_id=parent_id,
             source_root_id=source_root_id,
+            user_id=user_id,
         )
         session.add(folder)
         await session.flush()
diff --git a/backend/app/tasks/thumbs.py b/backend/app/tasks/thumbs.py
index 0a8bdb8..5364aa6 100644
--- a/backend/app/tasks/thumbs.py
+++ b/backend/app/tasks/thumbs.py
@@ -47,9 +47,16 @@ THUMB_SIZES = {
     'large': settings.thumbnails.large
 }
 
-def get_thumb_path(photo_id: str, size: str) -> str:
-    """Get the path for a thumbnail file"""
-    thumb_dir = f"/data/thumbs/{photo_id}"
+def get_thumb_path(photo_id: str, size: str, user_id: str = None) -> str:
+    """Get the path for a thumbnail file.
+
+    When user_id is provided, thumbnails are stored under a user-specific
+    subdirectory to enforce isolation between users.
+    """
+    if user_id:
+        thumb_dir = f"/data/thumbs/{user_id}/{photo_id}"
+    else:
+        thumb_dir = f"/data/thumbs/{photo_id}"
     os.makedirs(thumb_dir, exist_ok=True)
     return f"{thumb_dir}/{size}.{settings.thumbnails.format}"
 
@@ -302,7 +309,7 @@ async def _generate_thumbnails_async(photo_id: str, task):
 
             # Generate thumbnails for each size
             for size_name, size_value in THUMB_SIZES.items():
-                thumb_path = get_thumb_path(photo_id, size_name)
+                thumb_path = get_thumb_path(photo_id, size_name, photo.user_id)
                 generate_thumbnail(image, size_value, thumb_path)
                 
                 # Update database with thumbnail path
diff --git a/backend/bootstrap.py b/backend/bootstrap.py
new file mode 100644
index 0000000..4a012ed
--- /dev/null
+++ b/backend/bootstrap.py
@@ -0,0 +1,54 @@
+"""Post-init_db bootstrap: run or stamp Alembic migrations.
+
+On a FRESH Postgres install, init_db's create_all has already built the
+full schema from the current models. Running `alembic upgrade head` would
+fail because the older migrations try ADD COLUMN on columns that already
+exist. So we detect the fresh-install case (alembic_version table is
+missing or empty) and `stamp head` instead.
+
+On an EXISTING install, the alembic_version table has a revision and
+`upgrade head` applies only the new deltas.
+"""
+import subprocess
+import sys
+
+from sqlalchemy import create_engine, text, inspect
+from app.config import settings
+
+
+def run():
+    # Use a sync engine for this one-shot script.
+    sync_url = settings.database_url.replace("+asyncpg", "").replace("+aiosqlite", "")
+    engine = create_engine(sync_url)
+
+    with engine.connect() as conn:
+        inspector = inspect(engine)
+        tables = inspector.get_table_names()
+
+        if "alembic_version" not in tables:
+            # Fresh install — create_all built everything. Stamp head.
+            print("Fresh install detected — stamping alembic head")
+            subprocess.run(
+                [sys.executable, "-m", "alembic", "stamp", "head"],
+                check=True,
+            )
+        else:
+            row = conn.execute(text("SELECT version_num FROM alembic_version")).first()
+            if row is None:
+                print("Empty alembic_version — stamping head")
+                subprocess.run(
+                    [sys.executable, "-m", "alembic", "stamp", "head"],
+                    check=True,
+                )
+            else:
+                print(f"Existing install at revision {row[0]} — running alembic upgrade head")
+                subprocess.run(
+                    [sys.executable, "-m", "alembic", "upgrade", "head"],
+                    check=True,
+                )
+
+    engine.dispose()
+
+
+if __name__ == "__main__":
+    run()
diff --git a/backend/requirements.txt b/backend/requirements.txt
index 3c88c42..66652ce 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -54,6 +54,7 @@ aiofiles==23.2.1
 # Security and authentication
 python-jose[cryptography]==3.3.0
 passlib[bcrypt]==1.7.4
+bcrypt==4.0.1
 
 # Development
 pytest==7.4.4
diff --git a/docker-compose.sqlite.yml b/docker-compose.sqlite.yml
index 37adffb..dabc67f 100644
--- a/docker-compose.sqlite.yml
+++ b/docker-compose.sqlite.yml
@@ -24,6 +24,9 @@ services:
       - CELERY_RESULT_BACKEND=redis://redis:6379
       - PHOTO_DIRS=${PHOTO_DIRS:-/photos}
       - ALLOWED_ORIGINS=${ALLOWED_ORIGINS:-*}
+      - SECRET_KEY=${SECRET_KEY:-mulita-dev-secret-change-me}
+      - ACCESS_TOKEN_EXPIRE_MINUTES=${ACCESS_TOKEN_EXPIRE_MINUTES:-60}
+      - REFRESH_TOKEN_EXPIRE_DAYS=${REFRESH_TOKEN_EXPIRE_DAYS:-30}
       - LOG_LEVEL=${LOG_LEVEL:-INFO}
       - TZ=${TZ:-UTC}
     depends_on:
diff --git a/docker-compose.yml b/docker-compose.yml
index 106b832..af347a8 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -38,7 +38,11 @@ services:
     # Run Alembic migrations before starting uvicorn. On a fresh Postgres
     # the empty 0001 baseline is a no-op stamp; create_all in init_db then
     # builds the schema.
-    command: sh -c "python -c \"import asyncio; from app.database import init_db; asyncio.run(init_db())\" && alembic upgrade head && uvicorn app.main:app --host 0.0.0.0 --port 8000 --reload"
+    # init_db creates all tables from models (idempotent create_all),
+    # then Alembic runs migrations for existing installs. On fresh DBs
+    # create_all already built the full schema, so bootstrap.py stamps
+    # alembic head to skip redundant ALTER statements.
+    command: sh -c "python -c 'import asyncio; from app.database import init_db; asyncio.run(init_db())' && python bootstrap.py && uvicorn app.main:app --host 0.0.0.0 --port 8000 --reload"
     environment:
       - DATABASE_URL=postgresql+asyncpg://mulita:mulita@db:5432/mulita
       - REDIS_URL=redis://redis:6379
@@ -46,6 +50,9 @@ services:
       - CELERY_RESULT_BACKEND=redis://redis:6379
       - PHOTO_DIRS=${PHOTO_DIRS:-/photos}
       - ALLOWED_ORIGINS=${ALLOWED_ORIGINS:-*}
+      - SECRET_KEY=${SECRET_KEY:-mulita-dev-secret-change-me}
+      - ACCESS_TOKEN_EXPIRE_MINUTES=${ACCESS_TOKEN_EXPIRE_MINUTES:-60}
+      - REFRESH_TOKEN_EXPIRE_DAYS=${REFRESH_TOKEN_EXPIRE_DAYS:-30}
       - LOG_LEVEL=${LOG_LEVEL:-INFO}
       - TZ=${TZ:-UTC}
     depends_on:
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 887d828..58bb4cd 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -15,17 +15,19 @@ import { KeyboardHints } from './components/KeyboardHints'
 import { PreviewView } from './components/preview/PreviewView'
 import { FilterBar } from './components/filter/FilterBar'
 import { DiscardActionBar } from './components/discard/DiscardActionBar'
-import { SettingsDialog } from './components/dialogs/SettingsDialog'
+import { SettingsPage } from './components/dialogs/SettingsDialog'
 import { usePhotoStore } from './store/photoStore'
 import { useFilterStore } from './store/filterStore'
 import { useKeyboardShortcuts } from './hooks/useKeyboardShortcuts'
 import { useFilterUrlSync } from './hooks/useFilterUrlSync'
 import { usePhotosQuery } from './hooks/usePhotosQuery'
+import { AuthProvider, useAuth } from './contexts/AuthContext'
+import { LoginPage } from './components/auth/LoginPage'
+import { SetupPage } from './components/auth/SetupPage'
 
-function App() {
+function MainApp() {
   const [leftSidebarOpen, setLeftSidebarOpen] = useState(true)
   const [rightSidebarOpen, setRightSidebarOpen] = useState(true)
-  const [settingsOpen, setSettingsOpen] = useState(false)
   const viewMode = usePhotoStore((state) => state.viewMode)
   const currentSection = useFilterStore((s) => s.currentSection)
 
@@ -44,13 +46,13 @@ function App() {
     getFirstPhotoId: () => allPhotos?.[0]?.id ?? null,
   })
 
+  // Settings page is a full-page section — hide filter bar, right sidebar,
+  // and keyboard hints when it's active.
+  const isSettings = currentSection === 'settings'
+
   // Right sidebar stays open by default and shows whatever's selected
   // (or an empty state if nothing is). User can still toggle it manually.
-  // Note: deliberately NOT gated on viewMode — the preview overlay sits
-  // on top with z-[1000], so leaving the sidebar mounted underneath
-  // costs nothing visually and avoids the collapse-then-reopen layout
-  // shift the user would otherwise see every time they exit preview.
-  const showRightSidebar = rightSidebarOpen
+  const showRightSidebar = rightSidebarOpen && !isSettings
 
   return (
     <div className="flex flex-col h-screen bg-bg text-text">
@@ -70,7 +72,6 @@ function App() {
         >
           <LeftSidebar
             onCollapse={() => setLeftSidebarOpen(false)}
-            onOpenSettings={() => setSettingsOpen(true)}
           />
         </div>
 
@@ -79,14 +80,12 @@ function App() {
          *  across the sidebar. relative so the KeyboardHints overlay
          *  centers against this column, not the viewport. */}
         <div className="relative flex min-w-0 flex-1 flex-col">
-          <FilterBar />
-          <DiscardActionBar />
+          {!isSettings && <FilterBar />}
+          {!isSettings && <DiscardActionBar />}
           <div className="flex-1 overflow-auto">
-            {/* Section-level routing. The Map view replaces the timeline
-             *  with a Leaflet map of GPS-tagged photos; Duplicates gets its
-             *  own grouped grid; everything else falls through to the
-             *  filter-driven Timeline. */}
-            {currentSection === 'map' ? (
+            {currentSection === 'settings' ? (
+              <SettingsPage />
+            ) : currentSection === 'map' ? (
               <MapView />
             ) : currentSection === 'duplicates' ? (
               <DuplicatesView />
@@ -102,10 +101,7 @@ function App() {
               <Timeline />
             )}
           </div>
-          {/* Floating keyboard hints — bottom-center of the main column,
-           *  glassy. Mounted here so it's centered against the timeline,
-           *  not the viewport (which would be offset by the sidebars). */}
-          <KeyboardHints />
+          {!isSettings && <KeyboardHints />}
         </div>
 
         {/* Right Sidebar */}
@@ -127,13 +123,33 @@ function App() {
       {/* Preview overlay — covers TopBar when active */}
       {viewMode === 'preview' && <PreviewView />}
 
-      {/* Settings panel — admin/maintenance actions */}
-      <SettingsDialog
-        isOpen={settingsOpen}
-        onClose={() => setSettingsOpen(false)}
-      />
     </div>
   )
 }
 
+/** Auth-gated shell: shows setup, login, or the main app. */
+function App() {
+  return (
+    <AuthProvider>
+      <AuthGate />
+    </AuthProvider>
+  )
+}
+
+function AuthGate() {
+  const { user, isLoading, needsSetup } = useAuth()
+
+  if (isLoading) {
+    return (
+      <div className="flex min-h-screen items-center justify-center bg-bg">
+        <div className="text-text-muted">Loading&hellip;</div>
+      </div>
+    )
+  }
+
+  if (needsSetup) return <SetupPage />
+  if (!user) return <LoginPage />
+  return <MainApp />
+}
+
 export default App
\ No newline at end of file
diff --git a/frontend/src/components/admin/UserManagement.tsx b/frontend/src/components/admin/UserManagement.tsx
new file mode 100644
index 0000000..57ab1d3
--- /dev/null
+++ b/frontend/src/components/admin/UserManagement.tsx
@@ -0,0 +1,336 @@
+import { useState, useEffect, useCallback } from 'react'
+import { Plus, Pencil, UserX, Shield, User as UserIcon } from 'lucide-react'
+import { admin, type AdminUser } from '../../services/api'
+
+export function UserManagement() {
+  const [users, setUsers] = useState<AdminUser[]>([])
+  const [loading, setLoading] = useState(true)
+  const [showCreate, setShowCreate] = useState(false)
+  const [editingUser, setEditingUser] = useState<AdminUser | null>(null)
+  const [error, setError] = useState<string | null>(null)
+
+  const fetchUsers = useCallback(async () => {
+    try {
+      const data = await admin.listUsers()
+      setUsers(data.users)
+    } catch {
+      setError('Failed to load users.')
+    } finally {
+      setLoading(false)
+    }
+  }, [])
+
+  useEffect(() => {
+    fetchUsers()
+  }, [fetchUsers])
+
+  if (loading) {
+    return <div className="p-4 text-sm text-text-muted">Loading users&hellip;</div>
+  }
+
+  return (
+    <div className="space-y-4">
+      <div className="flex items-center justify-between">
+        <h3 className="text-sm font-semibold text-text">Users</h3>
+        <button
+          onClick={() => setShowCreate(true)}
+          className="flex items-center gap-1 rounded bg-accent px-2 py-1 text-xs text-white hover:bg-accent/80"
+        >
+          <Plus className="h-3 w-3" />
+          Add User
+        </button>
+      </div>
+
+      {error && (
+        <div className="rounded bg-red-900/30 px-3 py-2 text-xs text-red-300">
+          {error}
+        </div>
+      )}
+
+      <table className="w-full text-xs">
+        <thead>
+          <tr className="border-b border-border text-left text-text-muted">
+            <th className="pb-1 pr-4">Username</th>
+            <th className="pb-1 pr-4">Role</th>
+            <th className="pb-1 pr-4">Photos</th>
+            <th className="pb-1 pr-4">Status</th>
+            <th className="pb-1">Actions</th>
+          </tr>
+        </thead>
+        <tbody>
+          {users.map((u) => (
+            <tr key={u.id} className="border-b border-border/50">
+              <td className="py-1.5 pr-4">
+                <div className="flex items-center gap-1.5">
+                  {u.role === 'admin' ? (
+                    <Shield className="h-3 w-3 text-accent" />
+                  ) : (
+                    <UserIcon className="h-3 w-3 text-text-muted" />
+                  )}
+                  <span className="text-text">{u.username}</span>
+                </div>
+              </td>
+              <td className="py-1.5 pr-4 text-text-muted">{u.role}</td>
+              <td className="py-1.5 pr-4 text-text-muted">
+                {u.photo_count.toLocaleString()}
+              </td>
+              <td className="py-1.5 pr-4">
+                <span
+                  className={
+                    u.is_active
+                      ? 'text-green-400'
+                      : 'text-red-400'
+                  }
+                >
+                  {u.is_active ? 'Active' : 'Inactive'}
+                </span>
+              </td>
+              <td className="py-1.5">
+                <div className="flex gap-1">
+                  <button
+                    onClick={() => setEditingUser(u)}
+                    className="rounded p-1 text-text-muted hover:bg-bg hover:text-text"
+                    title="Edit user"
+                  >
+                    <Pencil className="h-3 w-3" />
+                  </button>
+                  {u.is_active && (
+                    <button
+                      onClick={async () => {
+                        if (!confirm(`Deactivate user "${u.username}"? Their photos will be preserved.`)) return
+                        try {
+                          await admin.deleteUser(u.id)
+                          fetchUsers()
+                        } catch (err: any) {
+                          setError(err.response?.data?.detail ?? 'Failed to deactivate user.')
+                        }
+                      }}
+                      className="rounded p-1 text-text-muted hover:bg-bg hover:text-red-400"
+                      title="Deactivate user"
+                    >
+                      <UserX className="h-3 w-3" />
+                    </button>
+                  )}
+                </div>
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+
+      {showCreate && (
+        <CreateUserModal
+          onClose={() => setShowCreate(false)}
+          onCreated={() => {
+            setShowCreate(false)
+            fetchUsers()
+          }}
+        />
+      )}
+
+      {editingUser && (
+        <EditUserModal
+          user={editingUser}
+          onClose={() => setEditingUser(null)}
+          onSaved={() => {
+            setEditingUser(null)
+            fetchUsers()
+          }}
+        />
+      )}
+    </div>
+  )
+}
+
+// ── Create User Modal ──────────────────────────────────────────────────
+
+function CreateUserModal({
+  onClose,
+  onCreated,
+}: {
+  onClose: () => void
+  onCreated: () => void
+}) {
+  const [username, setUsername] = useState('')
+  const [password, setPassword] = useState('')
+  const [role, setRole] = useState<'user' | 'admin'>('user')
+  const [error, setError] = useState<string | null>(null)
+  const [loading, setLoading] = useState(false)
+
+  const handleSubmit = async () => {
+    setError(null)
+    setLoading(true)
+    try {
+      await admin.createUser({ username: username.trim(), password, role })
+      onCreated()
+    } catch (err: any) {
+      setError(err.response?.data?.detail ?? 'Failed to create user.')
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  return (
+    <ModalOverlay onClose={onClose} title="Add User">
+      {error && (
+        <div className="rounded bg-red-900/30 px-3 py-2 text-xs text-red-300">
+          {error}
+        </div>
+      )}
+      <div className="space-y-3">
+        <Field label="Username">
+          <input
+            value={username}
+            onChange={(e) => setUsername(e.target.value)}
+            className="w-full rounded border border-border bg-bg px-2 py-1 text-xs text-text outline-none focus:border-accent"
+            autoFocus
+          />
+        </Field>
+        <Field label="Password">
+          <input
+            type="password"
+            value={password}
+            onChange={(e) => setPassword(e.target.value)}
+            className="w-full rounded border border-border bg-bg px-2 py-1 text-xs text-text outline-none focus:border-accent"
+          />
+        </Field>
+        <Field label="Role">
+          <select
+            value={role}
+            onChange={(e) => setRole(e.target.value as 'user' | 'admin')}
+            className="rounded border border-border bg-bg px-2 py-1 text-xs text-text outline-none focus:border-accent"
+          >
+            <option value="user">User</option>
+            <option value="admin">Admin</option>
+          </select>
+        </Field>
+      </div>
+      <div className="mt-4 flex justify-end gap-2">
+        <button
+          onClick={onClose}
+          className="rounded border border-border px-3 py-1 text-xs text-text hover:bg-bg"
+        >
+          Cancel
+        </button>
+        <button
+          onClick={handleSubmit}
+          disabled={loading}
+          className="rounded bg-accent px-3 py-1 text-xs text-white hover:bg-accent/80 disabled:opacity-50"
+        >
+          {loading ? 'Creating\u2026' : 'Create'}
+        </button>
+      </div>
+    </ModalOverlay>
+  )
+}
+
+// ── Edit User Modal ────────────────────────────────────────────────────
+
+function EditUserModal({
+  user,
+  onClose,
+  onSaved,
+}: {
+  user: AdminUser
+  onClose: () => void
+  onSaved: () => void
+}) {
+  const [role, setRole] = useState(user.role)
+  const [newPassword, setNewPassword] = useState('')
+  const [error, setError] = useState<string | null>(null)
+  const [loading, setLoading] = useState(false)
+
+  const handleSubmit = async () => {
+    setError(null)
+    setLoading(true)
+    try {
+      const data: { role?: string; new_password?: string } = {}
+      if (role !== user.role) data.role = role
+      if (newPassword) data.new_password = newPassword
+      if (Object.keys(data).length > 0) {
+        await admin.updateUser(user.id, data)
+      }
+      onSaved()
+    } catch (err: any) {
+      setError(err.response?.data?.detail ?? 'Failed to update user.')
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  return (
+    <ModalOverlay onClose={onClose} title={`Edit: ${user.username}`}>
+      {error && (
+        <div className="rounded bg-red-900/30 px-3 py-2 text-xs text-red-300">
+          {error}
+        </div>
+      )}
+      <div className="space-y-3">
+        <Field label="Role">
+          <select
+            value={role}
+            onChange={(e) => setRole(e.target.value as 'user' | 'admin')}
+            className="rounded border border-border bg-bg px-2 py-1 text-xs text-text outline-none focus:border-accent"
+          >
+            <option value="user">User</option>
+            <option value="admin">Admin</option>
+          </select>
+        </Field>
+        <Field label="New Password (leave blank to keep current)">
+          <input
+            type="password"
+            value={newPassword}
+            onChange={(e) => setNewPassword(e.target.value)}
+            className="w-full rounded border border-border bg-bg px-2 py-1 text-xs text-text outline-none focus:border-accent"
+            placeholder="Unchanged"
+          />
+        </Field>
+      </div>
+      <div className="mt-4 flex justify-end gap-2">
+        <button
+          onClick={onClose}
+          className="rounded border border-border px-3 py-1 text-xs text-text hover:bg-bg"
+        >
+          Cancel
+        </button>
+        <button
+          onClick={handleSubmit}
+          disabled={loading}
+          className="rounded bg-accent px-3 py-1 text-xs text-white hover:bg-accent/80 disabled:opacity-50"
+        >
+          {loading ? 'Saving\u2026' : 'Save'}
+        </button>
+      </div>
+    </ModalOverlay>
+  )
+}
+
+// ── Shared helpers ─────────────────────────────────────────────────────
+
+function ModalOverlay({
+  onClose: _onClose,
+  title,
+  children,
+}: {
+  onClose: () => void
+  title: string
+  children: React.ReactNode
+}) {
+  return (
+    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50" onClick={_onClose}>
+      <div className="w-full max-w-sm rounded-lg border border-border bg-surface p-5 shadow-xl" onClick={(e) => e.stopPropagation()}>
+        <h4 className="mb-3 text-sm font-semibold text-text">{title}</h4>
+        {children}
+      </div>
+    </div>
+  )
+}
+
+function Field({ label, children }: { label: string; children: React.ReactNode }) {
+  return (
+    <div className="space-y-1">
+      <label className="block text-[11px] text-text-muted">{label}</label>
+      {children}
+    </div>
+  )
+}
diff --git a/frontend/src/components/auth/LoginPage.tsx b/frontend/src/components/auth/LoginPage.tsx
new file mode 100644
index 0000000..ae8dbe2
--- /dev/null
+++ b/frontend/src/components/auth/LoginPage.tsx
@@ -0,0 +1,81 @@
+import { useState, type FormEvent } from 'react'
+import { useAuth } from '../../contexts/AuthContext'
+
+export function LoginPage() {
+  const { login } = useAuth()
+  const [username, setUsername] = useState('')
+  const [password, setPassword] = useState('')
+  const [error, setError] = useState<string | null>(null)
+  const [loading, setLoading] = useState(false)
+
+  const handleSubmit = async (e: FormEvent) => {
+    e.preventDefault()
+    setError(null)
+    setLoading(true)
+    try {
+      await login(username, password)
+    } catch (err: any) {
+      setError(
+        err.response?.data?.detail ?? 'Unable to sign in. Check your credentials.',
+      )
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  return (
+    <div className="flex min-h-screen items-center justify-center bg-bg px-4">
+      <form
+        onSubmit={handleSubmit}
+        className="w-full max-w-sm space-y-5 rounded-lg border border-border bg-surface p-8 shadow-xl"
+      >
+        <h1 className="text-center text-xl font-semibold text-text">
+          Sign in to Mulita
+        </h1>
+
+        {error && (
+          <div className="rounded bg-red-900/30 px-3 py-2 text-sm text-red-300">
+            {error}
+          </div>
+        )}
+
+        <div className="space-y-1">
+          <label htmlFor="login-user" className="block text-sm text-text-muted">
+            Username
+          </label>
+          <input
+            id="login-user"
+            type="text"
+            value={username}
+            onChange={(e) => setUsername(e.target.value)}
+            required
+            autoFocus
+            className="w-full rounded border border-border bg-bg px-3 py-2 text-sm text-text outline-none focus:border-accent"
+          />
+        </div>
+
+        <div className="space-y-1">
+          <label htmlFor="login-pass" className="block text-sm text-text-muted">
+            Password
+          </label>
+          <input
+            id="login-pass"
+            type="password"
+            value={password}
+            onChange={(e) => setPassword(e.target.value)}
+            required
+            className="w-full rounded border border-border bg-bg px-3 py-2 text-sm text-text outline-none focus:border-accent"
+          />
+        </div>
+
+        <button
+          type="submit"
+          disabled={loading}
+          className="w-full rounded bg-accent px-4 py-2 text-sm font-medium text-white transition-colors hover:bg-accent/80 disabled:opacity-50"
+        >
+          {loading ? 'Signing in\u2026' : 'Sign In'}
+        </button>
+      </form>
+    </div>
+  )
+}
diff --git a/frontend/src/components/auth/SetupPage.tsx b/frontend/src/components/auth/SetupPage.tsx
new file mode 100644
index 0000000..a02ca79
--- /dev/null
+++ b/frontend/src/components/auth/SetupPage.tsx
@@ -0,0 +1,119 @@
+import { useState, type FormEvent } from 'react'
+import { useAuth } from '../../contexts/AuthContext'
+import api from '../../services/api'
+
+export function SetupPage() {
+  const { onSetupComplete } = useAuth()
+  const [username, setUsername] = useState('')
+  const [password, setPassword] = useState('')
+  const [confirmPassword, setConfirmPassword] = useState('')
+  const [error, setError] = useState<string | null>(null)
+  const [loading, setLoading] = useState(false)
+
+  const handleSubmit = async (e: FormEvent) => {
+    e.preventDefault()
+    setError(null)
+
+    if (password !== confirmPassword) {
+      setError('Passwords do not match.')
+      return
+    }
+    if (password.length < 6) {
+      setError('Password must be at least 6 characters.')
+      return
+    }
+    if (username.trim().length < 2) {
+      setError('Username must be at least 2 characters.')
+      return
+    }
+
+    setLoading(true)
+    try {
+      const res = await api.post('/auth/setup', {
+        username: username.trim(),
+        password,
+      })
+      const { access_token, refresh_token } = res.data
+      await onSetupComplete(access_token, refresh_token)
+    } catch (err: any) {
+      setError(
+        err.response?.data?.detail ?? 'Setup failed. Please try again.',
+      )
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  return (
+    <div className="flex min-h-screen items-center justify-center bg-bg px-4">
+      <form
+        onSubmit={handleSubmit}
+        className="w-full max-w-sm space-y-5 rounded-lg border border-border bg-surface p-8 shadow-xl"
+      >
+        <div className="space-y-1 text-center">
+          <h1 className="text-xl font-semibold text-text">Welcome to Mulita</h1>
+          <p className="text-sm text-text-muted">
+            Create your admin account to get started.
+          </p>
+        </div>
+
+        {error && (
+          <div className="rounded bg-red-900/30 px-3 py-2 text-sm text-red-300">
+            {error}
+          </div>
+        )}
+
+        <div className="space-y-1">
+          <label htmlFor="setup-user" className="block text-sm text-text-muted">
+            Username
+          </label>
+          <input
+            id="setup-user"
+            type="text"
+            value={username}
+            onChange={(e) => setUsername(e.target.value)}
+            required
+            autoFocus
+            className="w-full rounded border border-border bg-bg px-3 py-2 text-sm text-text outline-none focus:border-accent"
+          />
+        </div>
+
+        <div className="space-y-1">
+          <label htmlFor="setup-pass" className="block text-sm text-text-muted">
+            Password
+          </label>
+          <input
+            id="setup-pass"
+            type="password"
+            value={password}
+            onChange={(e) => setPassword(e.target.value)}
+            required
+            className="w-full rounded border border-border bg-bg px-3 py-2 text-sm text-text outline-none focus:border-accent"
+          />
+        </div>
+
+        <div className="space-y-1">
+          <label htmlFor="setup-confirm" className="block text-sm text-text-muted">
+            Confirm Password
+          </label>
+          <input
+            id="setup-confirm"
+            type="password"
+            value={confirmPassword}
+            onChange={(e) => setConfirmPassword(e.target.value)}
+            required
+            className="w-full rounded border border-border bg-bg px-3 py-2 text-sm text-text outline-none focus:border-accent"
+          />
+        </div>
+
+        <button
+          type="submit"
+          disabled={loading}
+          className="w-full rounded bg-accent px-4 py-2 text-sm font-medium text-white transition-colors hover:bg-accent/80 disabled:opacity-50"
+        >
+          {loading ? 'Creating account\u2026' : 'Create Admin Account'}
+        </button>
+      </form>
+    </div>
+  )
+}
diff --git a/frontend/src/components/dialogs/SettingsDialog.tsx b/frontend/src/components/dialogs/SettingsDialog.tsx
index 684a991..0f2bd23 100644
--- a/frontend/src/components/dialogs/SettingsDialog.tsx
+++ b/frontend/src/components/dialogs/SettingsDialog.tsx
@@ -1,6 +1,5 @@
 import { useEffect, useState, useCallback, useRef } from 'react'
 import {
-  X,
   RefreshCw,
   Wrench,
   Film,
@@ -15,6 +14,7 @@ import {
   Sparkles,
   Activity,
   FolderSearch,
+  Shield,
 } from 'lucide-react'
 import clsx from 'clsx'
 import { useQuery, useQueryClient } from '@tanstack/react-query'
@@ -26,6 +26,8 @@ import {
   type WorkerStatus,
 } from '../../services/api'
 import { toast } from '../ToastContainer'
+import { useAuth } from '../../contexts/AuthContext'
+import { UserManagement } from '../admin/UserManagement'
 
 // React Query keys for the settings panels. Kept here (not in a shared
 // hook module) since they're internal to this dialog and used by the
@@ -40,24 +42,22 @@ const SETTINGS_SCAN_STATUS_KEY = ['settings', 'scan-status'] as const
 // the grid renders from. Imported via the canonical hook key.
 import { DUPLICATE_GROUPS_QUERY_KEY } from '../../hooks/useDuplicateGroupsQuery'
 
-interface SettingsDialogProps {
-  isOpen: boolean
-  onClose: () => void
-}
+type SettingsTab = 'library' | 'users'
+
+const TABS: { id: SettingsTab; label: string; adminOnly?: boolean }[] = [
+  { id: 'library', label: 'Library Management' },
+  { id: 'users', label: 'Users', adminOnly: true },
+]
 
 /**
- * Catch-all "settings + admin" panel. Currently exposes the maintenance
- * endpoints exposed by /api/v1/library/maintenance/* — regenerate
- * thumbnails (with filters), run the data-integrity cleanup, and trigger
- * a full library re-scan. The thumbnail stats block is the entry point
- * users will look at to understand what's going on after a scan.
- *
- * Each action is gated by an in-flight flag so double-clicks don't
- * stack background jobs, and the stats block re-fetches whenever the
- * dialog opens or after any action completes.
+ * Full-page settings view with tabbed navigation. Replaces the old
+ * modal dialog — renders as a top-level section in the main content
+ * area (like Timeline or MapView).
  */
-export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
+export function SettingsPage() {
+  const { isAdmin } = useAuth()
   const queryClient = useQueryClient()
+  const [activeTab, setActiveTab] = useState<SettingsTab>('library')
   const [showAllErrors, setShowAllErrors] = useState(false)
   // One key per action so each button has its own spinner without
   // blocking the others.
@@ -65,67 +65,45 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
 
   // All four panels fetch through React Query so cached data shows
   // instantly on reopen while a background refetch updates the numbers.
-  // `enabled: isOpen` avoids firing requests while the dialog is closed,
-  // but the cache entries survive between opens (default gcTime = 5m).
+  // All queries use scope=global so the admin sees cross-user totals.
   const thumbStatsQuery = useQuery({
     queryKey: SETTINGS_THUMB_STATS_KEY,
-    queryFn: library.maintenance.thumbnailStats,
-    enabled: isOpen,
-    // Treat as stale immediately so reopening the dialog triggers a
-    // background refetch on top of the cached view.
+    queryFn: () => library.maintenance.thumbnailStats('global'),
     staleTime: 0,
   })
   const libStatsQuery = useQuery({
     queryKey: SETTINGS_LIB_STATS_KEY,
-    queryFn: library.stats,
-    enabled: isOpen,
+    queryFn: () => library.stats('global'),
     staleTime: 0,
   })
-  // Worker status polls every 5s while the dialog is open — `refetchInterval`
-  // replaces the old setInterval loop. Missing-stats is relatively cheap
-  // but shares the same 5s rhythm to keep the orphan banner live.
   const workerStatusQuery = useQuery({
     queryKey: SETTINGS_WORKER_STATUS_KEY,
-    queryFn: library.maintenance.workerStatus,
-    enabled: isOpen,
-    refetchInterval: isOpen ? 5000 : false,
+    queryFn: () => library.maintenance.workerStatus('global'),
+    refetchInterval: 5000,
     staleTime: 0,
   })
   const missingStatsQuery = useQuery({
     queryKey: SETTINGS_MISSING_STATS_KEY,
     queryFn: library.maintenance.missingStats,
-    enabled: isOpen,
-    refetchInterval: isOpen ? 5000 : false,
+    refetchInterval: 5000,
     staleTime: 0,
   })
-  // Pipeline progress polls on the same 5s cadence as the worker status
-  // so both cards update together. Cheap query — ten COUNT(*)s on
-  // indexed columns.
   const pipelineStatsQuery = useQuery({
     queryKey: SETTINGS_PIPELINE_STATS_KEY,
-    queryFn: library.maintenance.pipelineStats,
-    enabled: isOpen,
-    refetchInterval: isOpen ? 5000 : false,
+    queryFn: () => library.maintenance.pipelineStats('global'),
+    refetchInterval: 5000,
     staleTime: 0,
   })
-  // Scan status — polls fast (2s) so the progress bar feels live during
-  // a scan, and slow (15s) when idle to cut chatter. `isScanning` is
-  // read from the latest fetched value so the cadence flips on its own
-  // the moment a scan kicks off or finishes.
   const scanStatusQuery = useQuery<ScanStatus>({
     queryKey: SETTINGS_SCAN_STATUS_KEY,
     queryFn: library.scanStatus,
-    enabled: isOpen,
     refetchInterval: (q) =>
-      isOpen ? ((q.state.data as ScanStatus | undefined)?.is_scanning ? 2000 : 15000) : false,
+      (q.state.data as ScanStatus | undefined)?.is_scanning ? 2000 : 15000,
     staleTime: 0,
   })
-  // Duplicates: shares the cache with DuplicatesView so a regroup
-  // triggered from Settings updates the grid view immediately.
   const duplicatesQuery = useQuery({
-    queryKey: DUPLICATE_GROUPS_QUERY_KEY,
-    queryFn: library.duplicates.groups,
-    enabled: isOpen,
+    queryKey: [...DUPLICATE_GROUPS_QUERY_KEY, 'global'],
+    queryFn: () => library.duplicates.groups('global'),
     staleTime: 0,
   })
 
@@ -170,29 +148,17 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
   // Surface fetch errors once (React Query de-dupes retries but we still
   // want a single toast so the user knows something went wrong).
   useEffect(() => {
-    if (!isOpen) return
     if (thumbStatsQuery.error || libStatsQuery.error) {
       console.error('Failed to load settings stats', thumbStatsQuery.error ?? libStatsQuery.error)
       toast.error('Could not load library stats')
     }
-  }, [isOpen, thumbStatsQuery.error, libStatsQuery.error])
+  }, [thumbStatsQuery.error, libStatsQuery.error])
   useEffect(() => {
-    if (!isOpen) return
     if (workerStatusQuery.error || missingStatsQuery.error) {
       console.error('Failed to load worker status', workerStatusQuery.error ?? missingStatsQuery.error)
       toast.error('Could not load worker status')
     }
-  }, [isOpen, workerStatusQuery.error, missingStatsQuery.error])
-
-  // Esc closes.
-  useEffect(() => {
-    if (!isOpen) return
-    const handler = (e: KeyboardEvent) => {
-      if (e.key === 'Escape') onClose()
-    }
-    window.addEventListener('keydown', handler)
-    return () => window.removeEventListener('keydown', handler)
-  }, [isOpen, onClose])
+  }, [workerStatusQuery.error, missingStatsQuery.error])
 
   const runAction = useCallback(
     async <T,>(
@@ -229,39 +195,40 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
     ) =>
       runAction(
         key,
-        () => library.maintenance.regenerateThumbnails(body),
+        () => library.maintenance.regenerateThumbnails(body, 'global'),
         'Regeneration queued',
         (r) => `${r.queued} photos queued, ${r.cleared_dirs} thumb dirs cleared`
       ),
     [runAction]
   )
 
-  if (!isOpen) return null
+  const visibleTabs = TABS.filter((t) => !t.adminOnly || isAdmin)
 
   return (
-    <div className="fixed inset-0 z-[2000]">
-      <div
-        className="absolute inset-0 bg-black/60 backdrop-blur-sm"
-        onClick={onClose}
-      />
-      <div className="absolute left-1/2 top-1/2 -translate-x-1/2 -translate-y-1/2">
-        <div className="relative z-10 flex max-h-[85vh] w-[640px] flex-col rounded-lg border border-border bg-surface shadow-2xl">
-          {/* Header */}
-          <div className="flex items-center justify-between border-b border-border px-5 py-3">
-            <h2 className="text-base font-semibold text-text">Settings</h2>
-            <button
-              onClick={onClose}
-              className="rounded p-1 text-text-muted hover:bg-surface-2 hover:text-text"
-              title="Close (Esc)"
-            >
-              <X className="h-4 w-4" />
-            </button>
-          </div>
+    <div className="flex h-full flex-col">
+      {/* Tab bar */}
+      <div className="flex items-center gap-1 border-b border-border bg-surface px-4 py-1.5">
+        {visibleTabs.map((tab) => (
+          <button
+            key={tab.id}
+            onClick={() => setActiveTab(tab.id)}
+            className={clsx(
+              'rounded px-3 py-1 text-xs font-medium transition-colors',
+              activeTab === tab.id
+                ? 'bg-primary/20 text-primary'
+                : 'text-text-muted hover:bg-surface-2 hover:text-text',
+            )}
+          >
+            {tab.label}
+          </button>
+        ))}
+      </div>
 
-          <div className="flex-1 overflow-y-auto p-5">
-            {/* ----------------------------------------------------- */}
-            {/* Library overview                                       */}
-            {/* ----------------------------------------------------- */}
+      {/* Tab content */}
+      <div className="flex-1 overflow-y-auto p-5">
+        <div className="mx-auto max-w-2xl">
+
+        {activeTab === 'library' && (<>
             <Section
               icon={<Database className="h-4 w-4" />}
               title="Library"
@@ -334,9 +301,6 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
               </div>
             </Section>
 
-            {/* ----------------------------------------------------- */}
-            {/* Pipeline progress — per-stage done/total               */}
-            {/* ----------------------------------------------------- */}
             <Section
               icon={<Activity className="h-4 w-4" />}
               title="Pipeline progress"
@@ -379,9 +343,6 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
               )}
             </Section>
 
-            {/* ----------------------------------------------------- */}
-            {/* Duplicate detection                                    */}
-            {/* ----------------------------------------------------- */}
             <Section
               icon={<Copy className="h-4 w-4" />}
               title="Duplicates"
@@ -433,9 +394,7 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
               </div>
             </Section>
 
-            {/* ----------------------------------------------------- */}
-            {/* Thumbnail maintenance                                  */}
-            {/* ----------------------------------------------------- */}
+
             <Section
               icon={<ImageIcon className="h-4 w-4" />}
               title="Thumbnails"
@@ -524,9 +483,6 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
               </div>
             </Section>
 
-            {/* ----------------------------------------------------- */}
-            {/* Worker fleet diagnostics                               */}
-            {/* ----------------------------------------------------- */}
             <Section
               icon={<Cpu className="h-4 w-4" />}
               title="Workers"
@@ -848,9 +804,6 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
               )}
             </Section>
 
-            {/* ----------------------------------------------------- */}
-            {/* Data integrity                                         */}
-            {/* ----------------------------------------------------- */}
             <Section
               icon={<Wrench className="h-4 w-4" />}
               title="Maintenance"
@@ -876,7 +829,17 @@ export function SettingsDialog({ isOpen, onClose }: SettingsDialogProps) {
                 </ActionButton>
               </div>
             </Section>
-          </div>
+        </>)}
+
+        {activeTab === 'users' && isAdmin && (
+            <Section
+              icon={<Shield className="h-4 w-4" />}
+              title="User Management"
+            >
+              <UserManagement />
+            </Section>
+        )}
+
         </div>
       </div>
     </div>
diff --git a/frontend/src/components/layout/LeftSidebar.tsx b/frontend/src/components/layout/LeftSidebar.tsx
index dfc1b26..7b27dd3 100644
--- a/frontend/src/components/layout/LeftSidebar.tsx
+++ b/frontend/src/components/layout/LeftSidebar.tsx
@@ -20,6 +20,9 @@ import {
   Users,
   Eye,
   EyeOff,
+  User as UserIcon,
+  LogOut,
+  Shield,
 } from 'lucide-react'
 import clsx from 'clsx'
 import { sourceFolders, photos as photosApi, type FolderTreeNode } from '../../services/api'
@@ -40,6 +43,7 @@ import {
 import { registerUndoable } from '../../store/undoStore'
 import type { Photo } from '../../types/photo'
 import { DeleteFolderDialog } from '../dialogs/DeleteFolderDialog'
+import { useAuth } from '../../contexts/AuthContext'
 
 interface TreeItem {
   id: string
@@ -55,10 +59,10 @@ interface TreeItem {
 
 interface LeftSidebarProps {
   onCollapse: () => void
-  onOpenSettings: () => void
 }
 
-export function LeftSidebar({ onCollapse, onOpenSettings }: LeftSidebarProps) {
+export function LeftSidebar({ onCollapse }: LeftSidebarProps) {
+  const { user, isAdmin, logout } = useAuth()
   const [expandedItems, setExpandedItems] = useState<Set<string>>(new Set(['library', 'folders', 'heaps']))
   // Inline rename state for source-root rows. Stores the id being edited
   // and the draft name. Double-click a folder row to start.
@@ -797,17 +801,40 @@ export function LeftSidebar({ onCollapse, onOpenSettings }: LeftSidebarProps) {
         <HeapsPanel />
       </div>
 
-      {/* Settings entry point — pinned to the bottom of the panel so it
-       *  sits out of the way of the library tree but is always reachable. */}
-      <div className="border-t border-border p-1.5">
-        <button
-          onClick={onOpenSettings}
-          className="flex w-full items-center gap-2 rounded px-2 py-1 text-[12px] text-text-muted hover:bg-surface-2 hover:text-text"
-          title="Settings"
-        >
-          <Settings className="h-3.5 w-3.5" />
-          Settings
-        </button>
+      {/* Bottom panel — user identity + settings, pinned below the tree. */}
+      <div className="border-t border-border p-1.5 space-y-0.5">
+        {/* User row */}
+        <div className="flex items-center gap-2 rounded px-2 py-1 text-[12px] text-text-muted">
+          <UserIcon className="h-3.5 w-3.5 flex-shrink-0" />
+          <span className="flex-1 truncate text-text">{user?.username}</span>
+          {isAdmin && (
+            <span className="rounded bg-accent/20 px-1 py-px text-[10px] leading-none text-accent flex-shrink-0">
+              <Shield className="inline h-2.5 w-2.5" />
+            </span>
+          )}
+          <button
+            onClick={logout}
+            className="rounded p-0.5 text-text-muted hover:bg-surface-2 hover:text-red-400 flex-shrink-0"
+            title="Sign out"
+          >
+            <LogOut className="h-3 w-3" />
+          </button>
+        </div>
+
+        {/* Settings — admin only, navigates to the settings section */}
+        {isAdmin && (
+          <button
+            onClick={() => navigateToSection('settings', {})}
+            className={clsx(
+              'flex w-full items-center gap-2 rounded px-2 py-1 text-[12px] hover:bg-surface-2 hover:text-text',
+              currentSection === 'settings' ? 'text-primary' : 'text-text-muted',
+            )}
+            title="Settings"
+          >
+            <Settings className="h-3.5 w-3.5" />
+            Settings
+          </button>
+        )}
       </div>
 
       <DeleteFolderDialog
diff --git a/frontend/src/components/layout/TopBar.tsx b/frontend/src/components/layout/TopBar.tsx
index db22eac..38b036c 100644
--- a/frontend/src/components/layout/TopBar.tsx
+++ b/frontend/src/components/layout/TopBar.tsx
@@ -96,22 +96,20 @@ export function TopBar({
           {MULIMAGO_ASCII}
         </pre>
       </div>
-      <div className="flex h-full items-end gap-2 self-stretch pb-1">
+      <div className="flex items-center gap-2">
+        <span className="text-[10px] font-serif text-black/80">
+          Built with hubris • {toRoman(new Date().getFullYear())}
+        </span>
         {!rightSidebarOpen && (
           <button
             onClick={onExpandRight}
-            className="self-center rounded bg-black/30 p-1.5 text-text-muted backdrop-blur-sm transition-colors hover:bg-black/50 hover:text-text"
+            className="rounded bg-black/30 p-1.5 text-text-muted backdrop-blur-sm transition-colors hover:bg-black/50 hover:text-text"
             title="Expand panel (I)"
             aria-label="Expand right panel"
           >
             <PanelRightOpen className="h-4 w-4" />
           </button>
         )}
-        <span
-          className="text-[10px] font-serif text-black/80"
-        >
-          Built with hubris • {toRoman(new Date().getFullYear())}
-        </span>
       </div>
     </header>
   )
diff --git a/frontend/src/contexts/AuthContext.tsx b/frontend/src/contexts/AuthContext.tsx
new file mode 100644
index 0000000..7828d12
--- /dev/null
+++ b/frontend/src/contexts/AuthContext.tsx
@@ -0,0 +1,170 @@
+import {
+  createContext,
+  useContext,
+  useState,
+  useEffect,
+  useCallback,
+  useRef,
+  type ReactNode,
+} from 'react'
+import api from '../services/api'
+
+export interface AuthUser {
+  id: string
+  username: string
+  email: string | null
+  role: 'admin' | 'user'
+  is_active: boolean
+}
+
+interface AuthContextValue {
+  user: AuthUser | null
+  isAdmin: boolean
+  isLoading: boolean
+  /** True when the backend has no users yet (first-run). */
+  needsSetup: boolean
+  login: (username: string, password: string) => Promise<void>
+  logout: () => void
+  /** Called after the setup endpoint creates the first admin. */
+  onSetupComplete: (accessToken: string, refreshToken: string) => Promise<void>
+}
+
+const AuthContext = createContext<AuthContextValue | null>(null)
+
+export function useAuth(): AuthContextValue {
+  const ctx = useContext(AuthContext)
+  if (!ctx) throw new Error('useAuth must be used within AuthProvider')
+  return ctx
+}
+
+// ── Token helpers ──────────────────────────────────────────────────────
+
+function getStoredToken(): string | null {
+  return localStorage.getItem('access_token')
+}
+
+function storeToken(token: string) {
+  localStorage.setItem('access_token', token)
+}
+
+function clearToken() {
+  localStorage.removeItem('access_token')
+}
+
+// ── Provider ───────────────────────────────────────────────────────────
+
+export function AuthProvider({ children }: { children: ReactNode }) {
+  const [user, setUser] = useState<AuthUser | null>(null)
+  const [isLoading, setIsLoading] = useState(true)
+  const [needsSetup, setNeedsSetup] = useState(false)
+  // Keep refresh token in memory only (not localStorage).
+  const refreshTokenRef = useRef<string | null>(null)
+  const refreshTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+
+  const isAdmin = user?.role === 'admin'
+
+  // Schedule a token refresh ~5 min before expiry.
+  const scheduleRefresh = useCallback((accessToken: string) => {
+    try {
+      const payload = JSON.parse(atob(accessToken.split('.')[1]))
+      const expiresAt = payload.exp * 1000
+      const refreshIn = Math.max(expiresAt - Date.now() - 5 * 60 * 1000, 10_000)
+
+      if (refreshTimerRef.current) clearTimeout(refreshTimerRef.current)
+      refreshTimerRef.current = setTimeout(async () => {
+        if (!refreshTokenRef.current) return
+        try {
+          const res = await api.post('/auth/refresh', {
+            refresh_token: refreshTokenRef.current,
+          })
+          const { access_token, refresh_token } = res.data
+          storeToken(access_token)
+          refreshTokenRef.current = refresh_token
+          scheduleRefresh(access_token)
+        } catch {
+          // Refresh failed — force re-login.
+          clearToken()
+          refreshTokenRef.current = null
+          setUser(null)
+        }
+      }, refreshIn)
+    } catch {
+      // Malformed token — ignore.
+    }
+  }, [])
+
+  const fetchMe = useCallback(async () => {
+    try {
+      const res = await api.get('/auth/me')
+      setUser(res.data)
+    } catch {
+      clearToken()
+      setUser(null)
+    }
+  }, [])
+
+  // Boot: check if setup is needed, then try to restore session.
+  useEffect(() => {
+    ;(async () => {
+      try {
+        const statusRes = await api.get('/auth/status')
+        if (!statusRes.data.setup_completed) {
+          setNeedsSetup(true)
+          setIsLoading(false)
+          return
+        }
+      } catch {
+        // Backend unreachable — fall through to login screen.
+      }
+
+      const token = getStoredToken()
+      if (token) {
+        await fetchMe()
+        scheduleRefresh(token)
+      }
+      setIsLoading(false)
+    })()
+
+    return () => {
+      if (refreshTimerRef.current) clearTimeout(refreshTimerRef.current)
+    }
+  }, [fetchMe, scheduleRefresh])
+
+  const login = useCallback(
+    async (username: string, password: string) => {
+      const res = await api.post('/auth/login', { username, password })
+      const { access_token, refresh_token } = res.data
+      storeToken(access_token)
+      refreshTokenRef.current = refresh_token
+      scheduleRefresh(access_token)
+      await fetchMe()
+    },
+    [fetchMe, scheduleRefresh],
+  )
+
+  const logout = useCallback(() => {
+    clearToken()
+    refreshTokenRef.current = null
+    if (refreshTimerRef.current) clearTimeout(refreshTimerRef.current)
+    setUser(null)
+  }, [])
+
+  const onSetupComplete = useCallback(
+    async (accessToken: string, refreshToken: string) => {
+      storeToken(accessToken)
+      refreshTokenRef.current = refreshToken
+      setNeedsSetup(false)
+      scheduleRefresh(accessToken)
+      await fetchMe()
+    },
+    [fetchMe, scheduleRefresh],
+  )
+
+  return (
+    <AuthContext.Provider
+      value={{ user, isAdmin, isLoading, needsSetup, login, logout, onSetupComplete }}
+    >
+      {children}
+    </AuthContext.Provider>
+  )
+}
diff --git a/frontend/src/hooks/useDuplicateGroupsQuery.ts b/frontend/src/hooks/useDuplicateGroupsQuery.ts
index 3768975..f1f134c 100644
--- a/frontend/src/hooks/useDuplicateGroupsQuery.ts
+++ b/frontend/src/hooks/useDuplicateGroupsQuery.ts
@@ -11,7 +11,7 @@ export const DUPLICATE_GROUPS_QUERY_KEY = ['library', 'duplicates'] as const
 export function useDuplicateGroupsQuery() {
   return useQuery<DuplicateGroupsResponse>({
     queryKey: DUPLICATE_GROUPS_QUERY_KEY,
-    queryFn: library.duplicates.groups,
+    queryFn: () => library.duplicates.groups(),
     staleTime: 30_000,
   })
 }
diff --git a/frontend/src/hooks/useLibraryStatsQuery.ts b/frontend/src/hooks/useLibraryStatsQuery.ts
index db580cb..d3ed23d 100644
--- a/frontend/src/hooks/useLibraryStatsQuery.ts
+++ b/frontend/src/hooks/useLibraryStatsQuery.ts
@@ -13,7 +13,7 @@ export const LIBRARY_STATS_QUERY_KEY = ['library', 'stats'] as const
 export function useLibraryStatsQuery() {
   return useQuery<LibraryStats>({
     queryKey: LIBRARY_STATS_QUERY_KEY,
-    queryFn: library.stats,
+    queryFn: () => library.stats(),
     staleTime: 30_000,
   })
 }
diff --git a/frontend/src/services/api.ts b/frontend/src/services/api.ts
index e90c0e3..04998fb 100644
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -14,6 +14,61 @@ const api = axios.create({
   },
 })
 
+// ── Auth interceptors ──────────────────────────────────────────────────
+
+// Attach the stored JWT to every outgoing request.
+api.interceptors.request.use((config) => {
+  const token = localStorage.getItem('access_token')
+  if (token) {
+    config.headers.Authorization = `Bearer ${token}`
+  }
+  return config
+})
+
+// On 401 responses, attempt one silent token refresh. If that also
+// fails, clear stored credentials so the AuthContext falls back to the
+// login screen on its next render.
+let isRefreshing = false
+let refreshSubscribers: ((token: string) => void)[] = []
+
+api.interceptors.response.use(
+  (response) => response,
+  async (error) => {
+    const original = error.config
+    if (error.response?.status !== 401 || original._retry) {
+      return Promise.reject(error)
+    }
+
+    // Skip retry for auth endpoints themselves to avoid loops.
+    if (original.url?.startsWith('/auth/')) {
+      return Promise.reject(error)
+    }
+
+    original._retry = true
+
+    if (!isRefreshing) {
+      isRefreshing = true
+      // The refresh token lives in AuthContext memory, not in
+      // localStorage. The interceptor can't access it directly, so we
+      // rely on the AuthContext's scheduled refresh to keep the access
+      // token fresh. If the access token is truly expired and no
+      // refresh has happened, we just force a logout.
+      localStorage.removeItem('access_token')
+      isRefreshing = false
+      // Reject — AuthContext will detect the missing token and show login.
+      return Promise.reject(error)
+    }
+
+    // Another request is already refreshing — queue this one.
+    return new Promise((resolve) => {
+      refreshSubscribers.push((token: string) => {
+        original.headers.Authorization = `Bearer ${token}`
+        resolve(api(original))
+      })
+    })
+  },
+)
+
 // Source Folders API. Source roots are config-driven now (PHOTO_DIRS in
 // .env → bootstrap on backend startup), so the UI only reads them and
 // optionally renames the display label.
@@ -394,15 +449,19 @@ export const library = {
     return response.data
   },
 
-  stats: async (): Promise<LibraryStats> => {
-    const response = await api.get('/library/stats')
+  stats: async (scope?: 'global'): Promise<LibraryStats> => {
+    const response = await api.get('/library/stats', {
+      params: scope ? { scope } : undefined,
+    })
     return response.data
   },
 
   /** Maintenance / admin actions surfaced via the Settings panel. */
   maintenance: {
-    thumbnailStats: async (): Promise<ThumbnailStats> => {
-      const response = await api.get('/library/maintenance/thumbnail-stats')
+    thumbnailStats: async (scope?: 'global'): Promise<ThumbnailStats> => {
+      const response = await api.get('/library/maintenance/thumbnail-stats', {
+        params: scope ? { scope } : undefined,
+      })
       return response.data
     },
 
@@ -413,28 +472,30 @@ export const library = {
         media_types?: MediaType[]
         only_failed?: boolean
         only_pending?: boolean
-      } = {}
+      } = {},
+      scope?: 'global',
     ): Promise<RegenerateResult> => {
       const response = await api.post(
         '/library/maintenance/regenerate-thumbnails',
-        body
+        body,
+        { params: scope ? { scope } : undefined },
       )
       return response.data
     },
 
-    /** Celery worker fleet diagnostics + recent task failures. Surfaced
-     *  in the Settings panel so users can debug stuck queues without
-     *  tailing container logs. */
-    workerStatus: async (): Promise<WorkerStatus> => {
-      const response = await api.get('/library/maintenance/worker-status')
+    /** Celery worker fleet diagnostics + recent task failures. */
+    workerStatus: async (scope?: 'global'): Promise<WorkerStatus> => {
+      const response = await api.get('/library/maintenance/worker-status', {
+        params: scope ? { scope } : undefined,
+      })
       return response.data
     },
 
-    /** Per-stage ingestion progress — thumbnails, EXIF, GPS, phash,
-     *  embeddings, object tags, OCR, faces, face clusters, duplicate
-     *  groups. Drives the Pipeline Progress card in Settings. */
-    pipelineStats: async (): Promise<PipelineStats> => {
-      const response = await api.get('/library/maintenance/pipeline-stats')
+    /** Per-stage ingestion progress. */
+    pipelineStats: async (scope?: 'global'): Promise<PipelineStats> => {
+      const response = await api.get('/library/maintenance/pipeline-stats', {
+        params: scope ? { scope } : undefined,
+      })
       return response.data
     },
 
@@ -477,8 +538,10 @@ export const library = {
   /** Duplicate groups computed by app.services.duplicates.regroup_duplicates.
    *  Drives the grouped grid view in the Duplicates section. */
   duplicates: {
-    groups: async (): Promise<DuplicateGroupsResponse> => {
-      const response = await api.get('/library/duplicates/groups')
+    groups: async (scope?: 'global'): Promise<DuplicateGroupsResponse> => {
+      const response = await api.get('/library/duplicates/groups', {
+        params: scope ? { scope } : undefined,
+      })
       return response.data
     },
   },
@@ -725,4 +788,45 @@ export const discard = {
   },
 }
 
+// Admin API — user management (admin only)
+export interface AdminUser {
+  id: string
+  username: string
+  email: string | null
+  role: 'admin' | 'user'
+  is_active: boolean
+  media_path: string
+  created_at: string | null
+  photo_count: number
+}
+
+export const admin = {
+  listUsers: async (): Promise<{ users: AdminUser[]; total: number }> => {
+    const response = await api.get('/admin/users')
+    return response.data
+  },
+
+  createUser: async (data: {
+    username: string
+    password: string
+    role: string
+  }): Promise<AdminUser> => {
+    const response = await api.post('/admin/users', data)
+    return response.data
+  },
+
+  updateUser: async (
+    userId: string,
+    data: { role?: string; is_active?: boolean; new_password?: string },
+  ): Promise<AdminUser> => {
+    const response = await api.patch(`/admin/users/${userId}`, data)
+    return response.data
+  },
+
+  deleteUser: async (userId: string): Promise<{ status: string }> => {
+    const response = await api.delete(`/admin/users/${userId}`)
+    return response.data
+  },
+}
+
 export default api
\ No newline at end of file