diff --git a/frontend/src/app/canvas/CanvasPage.tsx b/frontend/src/app/canvas/CanvasPage.tsx
index 3be1507..0f67438 100644
--- a/frontend/src/app/canvas/CanvasPage.tsx
+++ b/frontend/src/app/canvas/CanvasPage.tsx
@@ -3,7 +3,7 @@
  * Rendered inside the platform when a project is selected.
  */
 
-import React, { useCallback, useMemo, useRef } from 'react'
+import React, { useCallback, useEffect, useMemo, useRef } from 'react'
 import {
   ReactFlow,
   ReactFlowProvider,
@@ -181,6 +181,7 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
   const [renamingNodeId, setRenamingNodeId] = React.useState<string | null>(null)
   const [connectionFrom, setConnectionFrom] = React.useState<{ nodeId: string; sourceHandle?: string } | null>(null)
   const wrapperRef = useRef<HTMLDivElement | null>(null)
+  const canvasWrapperRef = useRef<HTMLDivElement | null>(null)
   const lastClickRef = useRef<{ clientX: number; clientY: number } | null>(null)
   const flowActionsRef = useRef<{ pasteAtViewportCenter: () => void; fitView: () => void } | null>(null)
   const [contextTarget, setContextTarget] = React.useState<null | { type: 'canvas'; clientX: number; clientY: number }>(null)
@@ -367,14 +368,6 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
     }
   }, [])
 
-  const onWheelCapture = useCallback((ev: React.WheelEvent) => {
-    const target = ev.target as HTMLElement
-    if (target.closest('.react-flow__node')) {
-      ev.preventDefault()
-      ev.stopPropagation()
-    }
-  }, [])
-
   const onCanvasContextMenu = useCallback((ev: React.MouseEvent) => {
     ev.preventDefault()
     lastClickRef.current = { clientX: ev.clientX, clientY: ev.clientY }
@@ -518,8 +511,8 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
             <ContextMenu>
               <ContextMenuTrigger asChild>
                 <div
+                  ref={canvasWrapperRef}
                   className="flex-1 min-h-0 w-full relative"
-                  onWheelCapture={onWheelCapture}
                   role="application"
                   aria-label="Graph canvas"
                   tabIndex={0}
@@ -556,7 +549,10 @@ export function CanvasPage({ projectId }: CanvasPageProps) {
                     <FlowFitViewOnLoad />
                     <FlowKeyboardShortcuts />
                     <ReactFlow
-                      nodes={nodes}
+                      nodes={nodes.map((n) => ({
+                        ...n,
+                        className: [n.className, 'nowheel'].filter(Boolean).join(' '),
+                      }))}
                       edges={edges}
                       onNodesChange={onNodesChange}
                       onEdgesChange={onEdgesChange}
diff --git a/frontend/src/components/nodes/RenderingNode.tsx b/frontend/src/components/nodes/RenderingNode.tsx
index b59483a..50f9a99 100644
--- a/frontend/src/components/nodes/RenderingNode.tsx
+++ b/frontend/src/components/nodes/RenderingNode.tsx
@@ -20,11 +20,12 @@ import { NodeHeaderTitle } from '../base/NodeHeaderTitle'
 import { NodeMenubar } from '../base/NodeMenubar'
 import { NodeStatusIndicator } from '../base/NodeStatusIndicator'
 import { MenubarItem, MenubarSeparator, MenubarSub, MenubarSubContent, MenubarSubTrigger } from '../ui/menubar'
-import { Sparkles, ZoomIn, ZoomOut, RotateCcw, RotateCw } from 'lucide-react'
+import { Sparkles, ZoomIn, ZoomOut, RotateCcw, RotateCw, Eye, FileCode } from 'lucide-react'
 import { InputHandle } from '../base/NodeHandles'
 import { TransformWrapper, TransformComponent } from 'react-zoom-pan-pinch'
 import { Input } from '../ui/input'
 import { Button } from '../ui/button'
+import { ToggleGroup, ToggleGroupItem } from '../ui/toggle-group'
 
 export type RenderingNodeData = {
     viewportWidth?: number
@@ -36,11 +37,16 @@ const DEFAULT_VIEWPORT_HEIGHT = 800
 
 type Props = AbstractNodeProps<RenderingNodeData>
 
+type ViewMode = 'preview' | 'raw'
+
 function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
     const [renderedContent, setRenderedContent] = useState<string | null>(null)
+    const [resolvedContent, setResolvedContent] = useState<string | null>(null)
     const [error, setError] = useState<null | { kind: string; message: string }>(null)
     const [loading, setLoading] = useState(false)
     const [retryCount, setRetryCount] = useState(0)
+    const [viewMode, setViewMode] = useState<ViewMode>('preview')
+    const [viewportFocused, setViewportFocused] = useState(false)
     const runIdRef = useRef(0)
     const loadingStartedAtRef = useRef<number | null>(null)
     const minLoadingTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null)
@@ -52,6 +58,8 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
     const srcId = incomingIds.length > 0 ? incomingIds[0] : null
     const srcNode = nodes.find((n: any) => n.id === srcId)
     const configTypeId = srcNode?.type === 'config' ? getConfigTypeId((srcNode.data ?? undefined) as Record<string, unknown> | undefined) : 'plantuml'
+    const configType = getConfigType(configTypeId)
+    const outputType = configType.outputType
     const sourceContent = srcNode?.type === 'config' ? getConfigContent((srcNode.data ?? undefined) as Record<string, unknown> | undefined) : ''
     const srcData = srcNode?.data ?? {}
 
@@ -158,12 +166,14 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
     useEffect(() => {
         if (!sourceContent && incomingIds.length > 0) {
             setRenderedContent(null)
+            setResolvedContent(null)
             setError({ kind: 'no-content', message: 'No content on connected configuration node' })
             setLoading(false)
             return
         }
         if (incomingIds.length === 0) {
             setRenderedContent(null)
+            setResolvedContent(null)
             setError(null)
             setLoading(false)
             return
@@ -433,17 +443,18 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
                     if (cancelled || thisRunId !== runIdRef.current) return
                     if (nunjucksErr) {
                         setRenderedContent(null)
+                        setResolvedContent(null)
                         setError({ kind: 'render', message: `Nunjucks: ${nunjucksErr.message}` })
                         setLoading(false)
                         return
                     }
 
-                    const resolvedContent = afterNunjucks
+                    setResolvedContent(afterNunjucks)
                     const typeRenderer = getConfigType(configTypeId)
 
                     try {
                         const renderOptions = configTypeId === 'wireframe' ? { width: viewportWidth, height: viewportHeight } : undefined
-                        const htmlOrSvg = await typeRenderer.render(resolvedContent, renderOptions)
+                        const htmlOrSvg = await typeRenderer.render(afterNunjucks, renderOptions)
                         if (cancelled || thisRunId !== runIdRef.current) return
                         setRenderedContent(htmlOrSvg)
                         setError(null)
@@ -574,13 +585,32 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
                 <BaseNodeHeaderRow icon={<Sparkles className="size-4" />} title={<NodeHeaderTitle nodeId={id} displayTitle={id} />} />
 
                 <BaseNodeContent>
-                    <div className="shrink-0 w-full">
+                    <div className="shrink-0 w-full flex items-center gap-2">
+                        {incomingIds.length > 0 && (
+                            <ToggleGroup
+                                type="single"
+                                value={viewMode}
+                                onValueChange={(v) => v && (v === 'preview' || v === 'raw') && setViewMode(v)}
+                                className="shrink-0"
+                                variant="outline"
+                                size="sm"
+                            >
+                                <ToggleGroupItem value="preview" aria-label="Preview" className="gap-1 px-2 text-xs">
+                                    <Eye className="size-3" />
+                                    Preview
+                                </ToggleGroupItem>
+                                <ToggleGroupItem value="raw" aria-label="Raw config" className="gap-1 px-2 text-xs">
+                                    <FileCode className="size-3" />
+                                    Raw
+                                </ToggleGroupItem>
+                            </ToggleGroup>
+                        )}
                         <NodeMenubar
                             nodeId={id}
                             nodeType="render"
                             nodeMenuExtraContent={
                                 <>
-                                    {isSvgOutput && (
+                                    {outputType === 'image' && (
                                         <MenubarSub>
                                             <MenubarSubTrigger className="text-xs">Viewport</MenubarSubTrigger>
                                             <MenubarSubContent className="min-w-[12rem] p-2">
@@ -698,18 +728,51 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
                             )
                         ) : loading ? (
                             <div className="flex min-h-0 flex-1 items-center justify-center text-xs text-muted-foreground">Rendering…</div>
+                        ) : viewMode === 'raw' ? (
+                            <div className="min-h-0 flex-1 w-full overflow-auto">
+                                <pre className="p-3 text-xs font-mono whitespace-pre-wrap break-words bg-muted/50 rounded m-2 min-h-0">
+                                    <code>{resolvedContent ?? '(no resolved config yet)'}</code>
+                                </pre>
+                            </div>
                         ) : renderedContent ? (
-                            isSvgOutput ? (
-                                <div className="rendering-viewport nodrag nopan relative min-h-0 flex-1 w-full min-w-0 overflow-hidden bg-white dark:bg-secondary">
+                            outputType === 'image' ? (
+                                <div
+                                    className="rendering-viewport nodrag nopan relative min-h-0 flex-1 w-full min-w-0 overflow-hidden bg-white dark:bg-secondary rounded outline-none"
+                                    tabIndex={0}
+                                    onFocus={() => setViewportFocused(true)}
+                                    onBlur={() => setViewportFocused(false)}
+                                >
                                     <TransformWrapper
                                         initialScale={1}
+                                        initialPositionX={0}
+                                        initialPositionY={0}
                                         minScale={0.2}
                                         maxScale={4}
-                                        centerOnInit
-                                        onInit={(ref) => ref?.centerView(1, 200, 'easeOut')}
-                                        panning={{ disabled: true }}
-                                        wheel={{ disabled: true }}
-                                        doubleClick={{ disabled: true }}
+                                        centerOnInit={false}
+                                        onInit={(ctx) => {
+                                            if (!ctx?.instance?.wrapperComponent || !ctx?.instance?.contentComponent) return
+                                            const fitToView = () => {
+                                                const wrapper = ctx.instance.wrapperComponent
+                                                const content = ctx.instance.contentComponent
+                                                if (!wrapper || !content) return
+                                                const wW = wrapper.clientWidth
+                                                const wH = wrapper.clientHeight
+                                                const cW = content.scrollWidth || content.clientWidth
+                                                const cH = content.scrollHeight || content.clientHeight
+                                                if (cW > 0 && cH > 0) {
+                                                    const scale = Math.min(wW / cW, wH / cH, 1)
+                                                    const posX = (wW - cW * scale) / 2
+                                                    const posY = (wH - cH * scale) / 2
+                                                    ctx.setTransform(posX, posY, scale, 0)
+                                                }
+                                            }
+                                            requestAnimationFrame(() => {
+                                                requestAnimationFrame(fitToView)
+                                            })
+                                        }}
+                                        panning={{ disabled: !selected && !viewportFocused }}
+                                        wheel={{ disabled: !selected && !viewportFocused }}
+                                        doubleClick={{ disabled: !selected && !viewportFocused }}
                                     >
                                         {({ zoomIn, zoomOut, resetTransform }) => (
                                             <>
@@ -739,13 +802,13 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
                                                         <RotateCcw className="size-3 max-w-[12px] max-h-[12px]" />
                                                     </button>
                                                 </div>
-                                                <div className="absolute inset-0 nodrag nopan">
+                                                <div className="absolute inset-0 nodrag nopan overflow-hidden">
                                                     <TransformComponent
                                                         wrapperClass="!w-full !h-full"
-                                                        contentClass="!w-full !h-full flex items-center justify-center nodrag nopan"
+                                                        contentClass="inline-flex nodrag nopan"
                                                     >
                                                         <div
-                                                            className="rendering-diagram flex items-center justify-center min-h-full min-w-full p-4 nodrag nopan"
+                                                            className="rendering-diagram inline-flex p-4 nodrag nopan"
                                                             dangerouslySetInnerHTML={{ __html: renderedContent }}
                                                         />
                                                     </TransformComponent>
@@ -766,11 +829,13 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
 
                 <BaseNodeFooter>
                     <NodeFooterEdgeIndicators nodeId={id} nodeType="render">
-                        {renderedContent
-                            ? `${getConfigType(configTypeId).label} · ${renderedContent.length} chars`
-                            : error
-                                ? 'Error'
-                                : '—'}
+                        {viewMode === 'raw'
+                            ? (resolvedContent != null ? `Raw · ${resolvedContent.length} chars` : '—')
+                            : renderedContent
+                                ? `${configType.label} · ${renderedContent.length} chars`
+                                : error
+                                    ? 'Error'
+                                    : '—'}
                     </NodeFooterEdgeIndicators>
                 </BaseNodeFooter>
             </BaseNode>
diff --git a/frontend/src/lib/configTypes.ts b/frontend/src/lib/configTypes.ts
index edbc011..e06dbcd 100644
--- a/frontend/src/lib/configTypes.ts
+++ b/frontend/src/lib/configTypes.ts
@@ -21,9 +21,14 @@ function isGroup(b: InsertBlockOrGroup): b is InsertBlockGroup {
 /** Optional options passed to render (e.g. node size for wireframe SVG). */
 export type RenderOptions = { width?: number; height?: number }
 
+/** How the renderer should display this type: HTML in a div, or image (SVG/PNG) in a viewport. */
+export type ConfigOutputType = 'html' | 'image'
+
 export type ConfigType = {
   id: ConfigTypeId
   label: string
+  /** How the RenderingNode should display output: 'html' (div) or 'image' (viewport). */
+  outputType: ConfigOutputType
   /** CodeMirror language key; used to pick the extension in ConfigNode. */
   language: ConfigTypeId
   /** Options under Insert → [type-specific]. Can be flat blocks or groups. */
@@ -129,6 +134,7 @@ export const CONFIG_TYPES: ConfigType[] = [
   {
     id: 'plantuml',
     label: 'Diagram',
+    outputType: 'image',
     language: 'plantuml',
     insertBlocks: PLANTUML_INSERT_BLOCKS,
     render: async (content: string) => {
@@ -167,6 +173,7 @@ export const CONFIG_TYPES: ConfigType[] = [
   {
     id: 'markdown',
     label: 'Markdown',
+    outputType: 'html',
     language: 'markdown',
     insertBlocks: MARKDOWN_INSERT_BLOCKS,
     render: renderMarkdown,
@@ -174,6 +181,7 @@ export const CONFIG_TYPES: ConfigType[] = [
   {
     id: 'wireframe',
     label: 'Wireframe',
+    outputType: 'image',
     language: 'markdown',
     insertBlocks: WIREFRAME_INSERT_BLOCKS,
     render: renderWireframe,