diff --git a/backend/app/routers/photos.py b/backend/app/routers/photos.py
index 6f73e41..7996841 100644
--- a/backend/app/routers/photos.py
+++ b/backend/app/routers/photos.py
@@ -16,9 +16,10 @@ import logging
 logger = logging.getLogger(__name__)
 
 from app.database import get_db
-from app.models import Photo, Folder, Tag, PhotoTag
+from app.models import Photo, Folder, Tag
 from app.models.folders import SourceRoot
 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.config import settings
 
@@ -120,6 +121,19 @@ async def list_photos(
             )
         )
 
+    # Tag filter — comma-separated tag ids, AND semantics. A photo must
+    # have a row in photo_tags for EVERY listed tag. Implemented as one
+    # subquery per tag id since SQLite doesn't have an efficient
+    # "set-contains-all" operator.
+    if tag_ids:
+        tag_id_list = [t.strip() for t in tag_ids.split(',') if t.strip()]
+        for tid in tag_id_list:
+            filters.append(
+                Photo.id.in_(
+                    select(photo_tags.c.photo_id).where(photo_tags.c.tag_id == tid)
+                )
+            )
+
     # Apply all filters
     if filters:
         query = query.where(and_(*filters))
@@ -153,21 +167,89 @@ async def list_photos(
         pages=(total + per_page - 1) // per_page
     )
 
-@router.get("/{photo_id}", response_model=PhotoResponse)
+@router.get("/{photo_id}")
 async def get_photo(
     photo_id: str,
     db: AsyncSession = Depends(get_db)
 ):
-    """Get single photo with full EXIF and tags"""
+    """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")
-    
-    return PhotoResponse.from_orm(photo)
+
+    # Fetch tags via the join table so we don't need to declare a
+    # relationship on the Photo model side.
+    tag_result = await db.execute(
+        select(Tag)
+        .join(photo_tags, Tag.id == photo_tags.c.tag_id)
+        .where(photo_tags.c.photo_id == photo_id)
+        .order_by(Tag.name.asc())
+    )
+    tags = tag_result.scalars().all()
+
+    base = PhotoResponse.from_orm(photo).dict()
+    base["tags"] = [
+        {"id": t.id, "name": t.name, "color": t.color} for t in tags
+    ]
+    return base
+
+
+@router.post("/{photo_id}/tags", status_code=201)
+async def add_photo_tags(
+    photo_id: str,
+    body: dict,
+    db: AsyncSession = Depends(get_db),
+):
+    """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")
+
+    tag_ids = body.get("tag_ids") or []
+    if not isinstance(tag_ids, list) or not tag_ids:
+        return {"status": "success", "added": 0}
+
+    existing = await db.execute(
+        select(photo_tags.c.tag_id).where(
+            photo_tags.c.photo_id == photo_id,
+            photo_tags.c.tag_id.in_(tag_ids),
+        )
+    )
+    existing_ids = {row[0] for row in existing.all()}
+    new_ids = [tid for tid in tag_ids if tid not in existing_ids]
+
+    if new_ids:
+        from sqlalchemy import insert
+        await db.execute(
+            insert(photo_tags),
+            [{"photo_id": photo_id, "tag_id": tid} for tid in new_ids],
+        )
+        await db.commit()
+
+    return {"status": "success", "added": len(new_ids)}
+
+
+@router.delete("/{photo_id}/tags/{tag_id}", status_code=204)
+async def remove_photo_tag(
+    photo_id: str,
+    tag_id: str,
+    db: AsyncSession = Depends(get_db),
+):
+    """Remove a tag from a photo. Removing a non-member is a no-op."""
+    from sqlalchemy import delete as sql_delete
+    await db.execute(
+        sql_delete(photo_tags).where(
+            photo_tags.c.photo_id == photo_id,
+            photo_tags.c.tag_id == tag_id,
+        )
+    )
+    await db.commit()
+    return None
 
 @router.get("/{photo_id}/thumb/{size}")
 async def get_thumbnail(
diff --git a/backend/app/routers/tags.py b/backend/app/routers/tags.py
index e7dc234..643a66d 100644
--- a/backend/app/routers/tags.py
+++ b/backend/app/routers/tags.py
@@ -1,27 +1,114 @@
 """
 Tags API router
 """
+from typing import Optional
 from fastapi import APIRouter, Depends, HTTPException
-from sqlalchemy import select, func
+from pydantic import BaseModel
+from sqlalchemy import select, func, insert, delete
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.database import get_db
 from app.models import Tag
+from app.models.tags import photo_tags
 
 router = APIRouter()
 
+
+# ── Schemas ───────────────────────────────────────────────────────────────
+
+class TagCreate(BaseModel):
+    name: str
+    color: Optional[str] = None
+
+
+class TagUpdate(BaseModel):
+    name: Optional[str] = None
+    color: Optional[str] = None
+
+
+# ── Endpoints ─────────────────────────────────────────────────────────────
+
 @router.get("")
 async def list_tags(db: AsyncSession = Depends(get_db)):
-    """List all tags with usage counts"""
-    result = await db.execute(select(Tag))
-    tags = result.scalars().all()
-    return tags
+    """List all tags with their photo counts."""
+    count_subq = (
+        select(
+            photo_tags.c.tag_id,
+            func.count(photo_tags.c.photo_id).label("photo_count"),
+        )
+        .group_by(photo_tags.c.tag_id)
+        .subquery()
+    )
+    stmt = (
+        select(Tag, count_subq.c.photo_count)
+        .outerjoin(count_subq, Tag.id == count_subq.c.tag_id)
+        .order_by(Tag.name.asc())
+    )
+    result = await db.execute(stmt)
+    rows = result.all()
 
-@router.post("")
-async def create_tag(name: str, color: str = None, db: AsyncSession = Depends(get_db)):
-    """Create a new tag"""
-    tag = Tag(name=name, color=color)
+    return [
+        {
+            "id": tag.id,
+            "name": tag.name,
+            "color": tag.color,
+            "photo_count": int(count or 0),
+        }
+        for tag, count in rows
+    ]
+
+
+@router.post("", status_code=201)
+async def create_tag(body: TagCreate, db: AsyncSession = Depends(get_db)):
+    """Create a new tag. Names are unique — re-creating an existing name
+    returns the existing row instead of erroring (idempotent for the
+    autocomplete UI flow)."""
+    name = (body.name or "").strip()
+    if not name:
+        raise HTTPException(status_code=400, detail="Tag name is required")
+
+    existing = await db.execute(select(Tag).where(Tag.name == name))
+    found = existing.scalar_one_or_none()
+    if found:
+        return {"id": found.id, "name": found.name, "color": found.color, "photo_count": 0}
+
+    tag = Tag(name=name, color=body.color)
     db.add(tag)
     await db.commit()
     await db.refresh(tag)
-    return tag
\ No newline at end of file
+    return {"id": tag.id, "name": tag.name, "color": tag.color, "photo_count": 0}
+
+
+@router.patch("/{tag_id}")
+async def update_tag(
+    tag_id: str, body: TagUpdate, db: AsyncSession = Depends(get_db)
+):
+    """Rename or recolor a tag."""
+    result = await db.execute(select(Tag).where(Tag.id == tag_id))
+    tag = result.scalar_one_or_none()
+    if not tag:
+        raise HTTPException(status_code=404, detail="Tag not found")
+
+    if body.name is not None:
+        name = body.name.strip()
+        if not name:
+            raise HTTPException(status_code=400, detail="Tag name is required")
+        tag.name = name
+    if body.color is not None:
+        tag.color = body.color or None
+
+    await db.commit()
+    await db.refresh(tag)
+    return {"id": tag.id, "name": tag.name, "color": tag.color}
+
+
+@router.delete("/{tag_id}", status_code=204)
+async def delete_tag(tag_id: str, db: AsyncSession = Depends(get_db)):
+    """Delete a tag. Photo associations cascade-delete via the FK."""
+    result = await db.execute(select(Tag).where(Tag.id == tag_id))
+    tag = result.scalar_one_or_none()
+    if not tag:
+        raise HTTPException(status_code=404, detail="Tag not found")
+    await db.delete(tag)
+    await db.commit()
+    return None
diff --git a/frontend/src/components/filter/ActiveFilterChips.tsx b/frontend/src/components/filter/ActiveFilterChips.tsx
index d5503ff..3920fb7 100644
--- a/frontend/src/components/filter/ActiveFilterChips.tsx
+++ b/frontend/src/components/filter/ActiveFilterChips.tsx
@@ -1,7 +1,7 @@
 import { X } from 'lucide-react'
 import { useQuery } from '@tanstack/react-query'
 import { useFilterStore, hasActiveFilters } from '../../store/filterStore'
-import { sourceFolders, heaps as heapsApi } from '../../services/api'
+import { sourceFolders, heaps as heapsApi, tags as tagsApi } from '../../services/api'
 
 export function ActiveFilterChips() {
   const f = useFilterStore()
@@ -24,6 +24,12 @@ export function ActiveFilterChips() {
   })
   const heap = f.heapId ? heaps.find((h) => h.id === f.heapId) : null
 
+  const { data: allTags = [] } = useQuery({
+    queryKey: ['tags'],
+    queryFn: tagsApi.list,
+    enabled: f.tagIds.length > 0,
+  })
+
   if (!hasActiveFilters(f)) return null
 
   const chips: { key: string; label: string; onRemove: () => void }[] = []
@@ -91,6 +97,14 @@ export function ActiveFilterChips() {
       onRemove: () => f.setHeapId(null),
     })
   }
+  for (const tagId of f.tagIds) {
+    const tag = allTags.find((t) => t.id === tagId)
+    chips.push({
+      key: `tag-${tagId}`,
+      label: `Tag: ${tag?.name ?? tagId}`,
+      onRemove: () => f.toggleTagId(tagId),
+    })
+  }
 
   return (
     <div className="flex flex-wrap items-center gap-2 border-b border-border bg-surface-2 px-4 py-2 text-xs">
diff --git a/frontend/src/components/filter/FilterBar.tsx b/frontend/src/components/filter/FilterBar.tsx
index 7f6e668..5cd011f 100644
--- a/frontend/src/components/filter/FilterBar.tsx
+++ b/frontend/src/components/filter/FilterBar.tsx
@@ -7,6 +7,7 @@ import {
   type FlagFilter,
   type SortField,
 } from '../../store/filterStore'
+import { useTagsQuery } from '../../hooks/useTagsQuery'
 
 const MEDIA_TYPES: { value: MediaType; label: string }[] = [
   { value: 'photo', label: 'Photo' },
@@ -47,6 +48,9 @@ export function FilterBar() {
   const flag = useFilterStore((s) => s.flag)
   const sortBy = useFilterStore((s) => s.sortBy)
   const sortOrder = useFilterStore((s) => s.sortOrder)
+  const tagIds = useFilterStore((s) => s.tagIds)
+  const toggleTagId = useFilterStore((s) => s.toggleTagId)
+  const { data: allTags = [] } = useTagsQuery()
 
   const setDateFrom = useFilterStore((s) => s.setDateFrom)
   const setDateTo = useFilterStore((s) => s.setDateTo)
@@ -170,6 +174,29 @@ export function FilterBar() {
         })}
       </Group>
 
+      {/* Tags */}
+      {allTags.length > 0 && (
+        <Group label="Tags">
+          {allTags.map((tag) => {
+            const active = tagIds.includes(tag.id)
+            return (
+              <button
+                key={tag.id}
+                onClick={() => toggleTagId(tag.id)}
+                className={clsx(
+                  'rounded px-2 py-1 transition-colors',
+                  active
+                    ? 'bg-primary text-white'
+                    : 'bg-surface-2 text-text-muted hover:bg-surface-offset hover:text-text'
+                )}
+              >
+                {tag.name}
+              </button>
+            )
+          })}
+        </Group>
+      )}
+
       {/* Sort */}
       <Group label="Sort">
         <select
diff --git a/frontend/src/components/layout/RightSidebar.tsx b/frontend/src/components/layout/RightSidebar.tsx
index a4e1061..767d61f 100644
--- a/frontend/src/components/layout/RightSidebar.tsx
+++ b/frontend/src/components/layout/RightSidebar.tsx
@@ -18,8 +18,16 @@ import { usePhotoStore } from '../../store/photoStore'
 import { photos as photosApi, heaps as heapsApi } from '../../services/api'
 import { useActiveHeapMembers } from '../../hooks/useActiveHeapMembersQuery'
 import { HEAPS_QUERY_KEY } from '../../hooks/useHeapsQuery'
+import { useTagsQuery, TAGS_QUERY_KEY } from '../../hooks/useTagsQuery'
+import { tags as tagsApi, type Tag } from '../../services/api'
 import { toast } from '../ToastContainer'
 
+interface PhotoTagSummary {
+  id: string
+  name: string
+  color: string | null
+}
+
 interface PhotoDetails {
   id: string
   filename: string
@@ -34,6 +42,7 @@ interface PhotoDetails {
   user_notes: string | null
   color_label: string | null
   exif_json: string | null
+  tags?: PhotoTagSummary[]
 }
 
 type ColorLabel = 'red' | 'orange' | 'yellow' | 'green' | 'blue' | 'purple'
@@ -100,7 +109,7 @@ export function RightSidebar() {
   const queryClient = useQueryClient()
 
   const [expandedSections, setExpandedSections] = useState<Set<string>>(
-    new Set(['basic', 'camera', 'location'])
+    new Set(['basic', 'camera', 'location', 'tags'])
   )
 
   const toggleSection = (section: string) => {
@@ -174,6 +183,46 @@ export function RightSidebar() {
     },
   })
 
+  // ── Tags state + mutations ──────────────────────────────────────────
+  const { data: allTags = [] } = useTagsQuery()
+  const [tagInput, setTagInput] = useState('')
+
+  const invalidateTagsAndPhoto = () => {
+    queryClient.invalidateQueries({ queryKey: TAGS_QUERY_KEY })
+    queryClient.invalidateQueries({ queryKey: ['photo', activePhotoId] })
+    queryClient.invalidateQueries({ queryKey: ['photos'] })
+  }
+
+  const addTagMutation = useMutation({
+    mutationFn: async (name: string) => {
+      // Idempotent create — backend returns existing row if name matches.
+      const created = await tagsApi.create(name)
+      if (activePhotoId) {
+        await tagsApi.addToPhoto(activePhotoId, [created.id])
+      }
+      return created
+    },
+    onSuccess: () => invalidateTagsAndPhoto(),
+    onError: (e: any) =>
+      toast.error('Add tag failed', e?.message || 'Unknown error'),
+  })
+
+  const attachExistingTagMutation = useMutation({
+    mutationFn: (tagId: string) =>
+      tagsApi.addToPhoto(activePhotoId!, [tagId]),
+    onSuccess: () => invalidateTagsAndPhoto(),
+    onError: (e: any) =>
+      toast.error('Add tag failed', e?.message || 'Unknown error'),
+  })
+
+  const removeTagMutation = useMutation({
+    mutationFn: (tagId: string) =>
+      tagsApi.removeFromPhoto(activePhotoId!, tagId),
+    onSuccess: () => invalidateTagsAndPhoto(),
+    onError: (e: any) =>
+      toast.error('Remove tag failed', e?.message || 'Unknown error'),
+  })
+
   // Local drafts for the editable text fields. These mirror the server value
   // but stay independent while the user is typing, so we don't fight focus or
   // clobber edits with stale refetches.
@@ -520,6 +569,26 @@ export function RightSidebar() {
                 <div className="text-xs text-text-muted">No GPS data</div>
               )}
             </Section>
+
+            {/* Tags */}
+            <Section
+              title="Tags"
+              expanded={expandedSections.has('tags')}
+              onToggle={() => toggleSection('tags')}
+            >
+              <TagsEditor
+                photoTags={photo.tags ?? []}
+                allTags={allTags}
+                tagInput={tagInput}
+                onTagInputChange={setTagInput}
+                onAttachExisting={(id) => attachExistingTagMutation.mutate(id)}
+                onCreateAndAttach={(name) => {
+                  addTagMutation.mutate(name)
+                  setTagInput('')
+                }}
+                onRemove={(id) => removeTagMutation.mutate(id)}
+              />
+            </Section>
           </>
         )}
 
@@ -574,6 +643,129 @@ function Section({
   )
 }
 
+interface TagsEditorProps {
+  photoTags: PhotoTagSummary[]
+  allTags: Tag[]
+  tagInput: string
+  onTagInputChange: (value: string) => void
+  onAttachExisting: (id: string) => void
+  onCreateAndAttach: (name: string) => void
+  onRemove: (id: string) => void
+}
+
+function TagsEditor({
+  photoTags,
+  allTags,
+  tagInput,
+  onTagInputChange,
+  onAttachExisting,
+  onCreateAndAttach,
+  onRemove,
+}: TagsEditorProps) {
+  const trimmed = tagInput.trim()
+  const lowerTrimmed = trimmed.toLowerCase()
+  const photoTagIds = new Set(photoTags.map((t) => t.id))
+
+  // Suggestions: tags whose name contains the input AND that aren't
+  // already on the photo. Capped at 6 to keep the dropdown short.
+  const suggestions = trimmed
+    ? allTags
+        .filter(
+          (t) =>
+            !photoTagIds.has(t.id) &&
+            t.name.toLowerCase().includes(lowerTrimmed)
+        )
+        .slice(0, 6)
+    : []
+
+  const exactMatch = trimmed
+    ? allTags.find((t) => t.name.toLowerCase() === lowerTrimmed)
+    : null
+
+  const handleSubmit = () => {
+    if (!trimmed) return
+    if (exactMatch) {
+      if (!photoTagIds.has(exactMatch.id)) {
+        onAttachExisting(exactMatch.id)
+      }
+      onTagInputChange('')
+    } else {
+      onCreateAndAttach(trimmed)
+    }
+  }
+
+  return (
+    <div className="space-y-2">
+      {/* Existing tag chips */}
+      {photoTags.length > 0 ? (
+        <div className="flex flex-wrap gap-1">
+          {photoTags.map((tag) => (
+            <span
+              key={tag.id}
+              className="flex items-center gap-1 rounded bg-surface-2 px-2 py-0.5 text-xs text-text"
+              style={tag.color ? { backgroundColor: `${tag.color}33`, color: tag.color } : undefined}
+            >
+              {tag.name}
+              <button
+                onClick={() => onRemove(tag.id)}
+                className="rounded p-0.5 opacity-60 hover:bg-surface-offset hover:opacity-100"
+                title="Remove tag"
+              >
+                <X className="h-3 w-3" />
+              </button>
+            </span>
+          ))}
+        </div>
+      ) : (
+        <div className="text-xs text-text-faint">No tags</div>
+      )}
+
+      {/* Add tag input + suggestions */}
+      <div className="relative">
+        <input
+          type="text"
+          value={tagInput}
+          onChange={(e) => onTagInputChange(e.target.value)}
+          onKeyDown={(e) => {
+            if (e.key === 'Enter') {
+              e.preventDefault()
+              handleSubmit()
+            } else if (e.key === 'Escape') {
+              onTagInputChange('')
+            }
+          }}
+          placeholder="Add tag…"
+          className="w-full rounded border border-border bg-bg px-2 py-1 text-xs text-text placeholder-text-faint focus:border-primary focus:outline-none"
+        />
+        {suggestions.length > 0 && (
+          <div className="mt-1 rounded border border-border bg-bg shadow-md">
+            {suggestions.map((s) => (
+              <button
+                key={s.id}
+                onClick={() => {
+                  onAttachExisting(s.id)
+                  onTagInputChange('')
+                }}
+                className="block w-full px-2 py-1 text-left text-xs text-text hover:bg-surface-2"
+              >
+                {s.name}
+              </button>
+            ))}
+          </div>
+        )}
+        {trimmed && !exactMatch && (
+          <button
+            onClick={handleSubmit}
+            className="mt-1 w-full rounded border border-dashed border-primary/50 px-2 py-1 text-left text-xs text-primary hover:bg-primary/10"
+          >
+            + Create "{trimmed}"
+          </button>
+        )}
+      </div>
+    </div>
+  )
+}
+
 function Field({ label, value }: { label: string; value: string }) {
   return (
     <div>
diff --git a/frontend/src/hooks/useFilterUrlSync.ts b/frontend/src/hooks/useFilterUrlSync.ts
index 54fb202..fc5f866 100644
--- a/frontend/src/hooks/useFilterUrlSync.ts
+++ b/frontend/src/hooks/useFilterUrlSync.ts
@@ -71,6 +71,12 @@ function parseUrl(): Partial<FilterState> {
   const folderId = sp.get('folder_id')
   if (folderId) out.folderId = folderId
 
+  const tagIds = sp.get('tag_ids')
+  if (tagIds) {
+    const ids = tagIds.split(',').map((t) => t.trim()).filter(Boolean)
+    if (ids.length > 0) out.tagIds = ids
+  }
+
   const sortBy = sp.get('sort')
   if (sortBy && ALLOWED_SORT_FIELDS.includes(sortBy as SortField)) {
     out.sortBy = sortBy as SortField
@@ -95,6 +101,7 @@ function writeUrl(f: FilterState) {
   if (f.flag !== 'any') sp.set('flag', f.flag)
   if (f.heapId) sp.set('heap_id', f.heapId)
   if (f.folderId) sp.set('folder_id', f.folderId)
+  if (f.tagIds.length > 0) sp.set('tag_ids', f.tagIds.join(','))
   if (f.sortBy !== 'taken_at') sp.set('sort', f.sortBy)
   if (f.sortOrder !== 'desc') sp.set('order', f.sortOrder)
 
diff --git a/frontend/src/hooks/usePhotosQuery.ts b/frontend/src/hooks/usePhotosQuery.ts
index 749d1c0..7f61579 100644
--- a/frontend/src/hooks/usePhotosQuery.ts
+++ b/frontend/src/hooks/usePhotosQuery.ts
@@ -20,6 +20,7 @@ export function usePhotosQuery() {
   const flag = useFilterStore((s) => s.flag)
   const heapId = useFilterStore((s) => s.heapId)
   const folderId = useFilterStore((s) => s.folderId)
+  const tagIds = useFilterStore((s) => s.tagIds)
   const sortBy = useFilterStore((s) => s.sortBy)
   const sortOrder = useFilterStore((s) => s.sortOrder)
 
@@ -35,10 +36,11 @@ export function usePhotosQuery() {
         flag,
         heapId,
         folderId,
+        tagIds,
         sortBy,
         sortOrder,
       }),
-    [q, dateFrom, dateTo, mediaTypes, ratingMin, colorLabel, flag, heapId, folderId, sortBy, sortOrder]
+    [q, dateFrom, dateTo, mediaTypes, ratingMin, colorLabel, flag, heapId, folderId, tagIds, sortBy, sortOrder]
   )
 
   return useQuery({
diff --git a/frontend/src/hooks/useTagsQuery.ts b/frontend/src/hooks/useTagsQuery.ts
new file mode 100644
index 0000000..78fbfbb
--- /dev/null
+++ b/frontend/src/hooks/useTagsQuery.ts
@@ -0,0 +1,12 @@
+import { useQuery } from '@tanstack/react-query'
+import { tags as tagsApi, type Tag } from '../services/api'
+
+export const TAGS_QUERY_KEY = ['tags'] as const
+
+export function useTagsQuery() {
+  return useQuery<Tag[]>({
+    queryKey: TAGS_QUERY_KEY,
+    queryFn: tagsApi.list,
+    staleTime: 30_000,
+  })
+}
diff --git a/frontend/src/services/api.ts b/frontend/src/services/api.ts
index 21ee20d..e6fd91a 100644
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -191,32 +191,43 @@ export const heaps = {
 }
 
 // Tags API
+export interface Tag {
+  id: string
+  name: string
+  color: string | null
+  photo_count: number
+}
+
 export const tags = {
-  list: async () => {
+  list: async (): Promise<Tag[]> => {
     const response = await api.get('/tags')
     return response.data
   },
 
-  create: async (name: string, color?: string) => {
-    const response = await api.post('/tags', {
-      name,
-      color,
-    })
+  create: async (name: string, color?: string): Promise<Tag> => {
+    const response = await api.post('/tags', { name, color })
     return response.data
   },
 
-  update: async (tagId: string, data: {
-    name?: string
-    color?: string
-  }) => {
+  update: async (tagId: string, data: { name?: string; color?: string }): Promise<Tag> => {
     const response = await api.patch(`/tags/${tagId}`, data)
     return response.data
   },
 
-  delete: async (tagId: string) => {
-    const response = await api.delete(`/tags/${tagId}`)
+  delete: async (tagId: string): Promise<void> => {
+    await api.delete(`/tags/${tagId}`)
+  },
+
+  /** Add one or more tags to a photo. */
+  addToPhoto: async (photoId: string, tagIds: string[]) => {
+    const response = await api.post(`/photos/${photoId}/tags`, { tag_ids: tagIds })
     return response.data
   },
+
+  /** Remove a tag from a photo. */
+  removeFromPhoto: async (photoId: string, tagId: string): Promise<void> => {
+    await api.delete(`/photos/${photoId}/tags/${tagId}`)
+  },
 }
 
 // Discard API
diff --git a/frontend/src/store/filterStore.ts b/frontend/src/store/filterStore.ts
index 3931304..953d35f 100644
--- a/frontend/src/store/filterStore.ts
+++ b/frontend/src/store/filterStore.ts
@@ -24,6 +24,8 @@ export interface FilterState {
   heapId: string | null
   /** When set, restrict to photos in this folder. */
   folderId: string | null
+  /** Restrict to photos that have ALL of these tag ids (AND semantics). */
+  tagIds: string[]
   sortBy: SortField
   sortOrder: SortOrder
 }
@@ -40,6 +42,8 @@ interface FilterStore extends FilterState {
   setFlag: (flag: FlagFilter) => void
   setHeapId: (id: string | null) => void
   setFolderId: (id: string | null) => void
+  setTagIds: (ids: string[]) => void
+  toggleTagId: (id: string) => void
   setSortBy: (field: SortField) => void
   setSortOrder: (order: SortOrder) => void
   toggleSortOrder: () => void
@@ -61,6 +65,7 @@ export const INITIAL_FILTERS: FilterState = {
   flag: 'any',
   heapId: null,
   folderId: null,
+  tagIds: [],
   sortBy: 'taken_at',
   sortOrder: 'desc',
 }
@@ -83,6 +88,13 @@ export const useFilterStore = create<FilterStore>((set) => ({
   setFlag: (flag) => set({ flag }),
   setHeapId: (heapId) => set({ heapId }),
   setFolderId: (folderId) => set({ folderId }),
+  setTagIds: (tagIds) => set({ tagIds }),
+  toggleTagId: (id) =>
+    set((s) => ({
+      tagIds: s.tagIds.includes(id)
+        ? s.tagIds.filter((t) => t !== id)
+        : [...s.tagIds, id],
+    })),
   setSortBy: (sortBy) => set({ sortBy }),
   setSortOrder: (sortOrder) => set({ sortOrder }),
   toggleSortOrder: () =>
@@ -108,6 +120,7 @@ export function filtersToParams(f: FilterState): Record<string, string | number>
   if (f.flag === 'discarded') params.is_discarded = 'true'
   if (f.heapId) params.heap_id = f.heapId
   if (f.folderId) params.folder_id = f.folderId
+  if (f.tagIds.length > 0) params.tag_ids = f.tagIds.join(',')
   params.sort = f.sortBy
   params.order = f.sortOrder
   return params
@@ -124,6 +137,7 @@ export function hasActiveFilters(f: FilterState): boolean {
     f.colorLabel !== null ||
     f.flag !== 'any' ||
     f.heapId !== null ||
-    f.folderId !== null
+    f.folderId !== null ||
+    f.tagIds.length > 0
   )
 }