diff --git a/src/App.tsx b/src/App.tsx
index a37661c..6dbdfa0 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -8,6 +8,8 @@ import {
   addEdge,
   applyNodeChanges,
   applyEdgeChanges,
+  useNodesInitialized,
+  useReactFlow,
   type Node,
   type Edge,
   type Connection,
@@ -107,6 +109,18 @@ const PROJECT_VERSION = 1
 
 export type ProjectMessage = { type: 'success' | 'error'; text: string }
 
+/** Calls fitView when nodes are initialized (e.g. after load/import). Must be rendered inside ReactFlowProvider. */
+function FlowFitViewOnLoad() {
+  const nodesInitialized = useNodesInitialized()
+  const { fitView } = useReactFlow()
+  React.useEffect(() => {
+    if (nodesInitialized) {
+      fitView?.({ duration: 200 })
+    }
+  }, [nodesInitialized, fitView])
+  return null
+}
+
 export default function App() {
   const { theme } = useTheme()
   const {
@@ -488,6 +502,7 @@ export default function App() {
                     </div>
                   )}
                   <ReactFlowProvider initialNodes={nodes} initialEdges={edges} fitView>
+                    <FlowFitViewOnLoad />
                     <ReactFlow
                       nodes={nodes}
                       edges={edges}
@@ -508,6 +523,9 @@ export default function App() {
                       fitView
                       onInit={onInit}
                       nodeDragThreshold={1}
+                      nodesDraggable
+                      nodesConnectable
+                      elementsSelectable
                     >
                       <Background variant="dots" gap={20} />
                       <Controls />
diff --git a/src/components/nodes/RenderingNode.tsx b/src/components/nodes/RenderingNode.tsx
index 9b14e07..d2fb8c1 100644
--- a/src/components/nodes/RenderingNode.tsx
+++ b/src/components/nodes/RenderingNode.tsx
@@ -20,10 +20,11 @@ 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 } from 'lucide-react'
+import { Sparkles, ZoomIn, ZoomOut, RotateCcw, RotateCw } 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'
 
 export type RenderingNodeData = {
     viewportWidth?: number
@@ -39,6 +40,7 @@ function RenderingNodeComponent({ id, data, width, height }: Props) {
     const [renderedContent, setRenderedContent] = 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 runIdRef = useRef(0)
     const loadingStartedAtRef = useRef<number | null>(null)
     const minLoadingTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null)
@@ -151,6 +153,8 @@ function RenderingNodeComponent({ id, data, width, height }: Props) {
         [nodes, connectedNodeIds]
     )
 
+    const RENDER_DEBOUNCE_MS = 250
+
     useEffect(() => {
         if (!sourceContent && incomingIds.length > 0) {
             setRenderedContent(null)
@@ -473,16 +477,17 @@ function RenderingNodeComponent({ id, data, width, height }: Props) {
             }
         }
 
-        run()
+        const debounceTimer = setTimeout(run, RENDER_DEBOUNCE_MS)
         return () => {
             cancelled = true
+            clearTimeout(debounceTimer)
             if (minLoadingTimeoutRef.current != null) {
                 clearTimeout(minLoadingTimeoutRef.current)
                 minLoadingTimeoutRef.current = null
             }
         }
-        // Only re-run when inputs that affect the resolved output change (signatures + source).
-    }, [id, sourceContent, configTypeId, configSignature, edgesSignature, variablesSignature, functionsSignature, viewportWidth, viewportHeight])
+        // Only re-run when inputs that affect the resolved output change (signatures + source). Debounced to avoid excessive re-renders while typing. retryCount triggers re-run on Retry.
+    }, [id, sourceContent, configTypeId, configSignature, edgesSignature, variablesSignature, functionsSignature, viewportWidth, viewportHeight, retryCount])
 
     const dimensions =
         width != null && height != null && width > 0 && height > 0
@@ -646,7 +651,19 @@ function RenderingNodeComponent({ id, data, width, height }: Props) {
                             ) : srcData?.errorHtml ? (
                                 <div className="p-3 text-xs text-red-700 dark:text-red-400" dangerouslySetInnerHTML={{ __html: String(srcData.errorHtml) }} />
                             ) : (
-                                <div className="p-3 text-xs text-red-700 dark:text-red-400">{error.message}</div>
+                                <div className="flex flex-col gap-2 p-3">
+                                    <p className="text-xs text-red-700 dark:text-red-400">{error.message}</p>
+                                    <Button
+                                        type="button"
+                                        variant="outline"
+                                        size="sm"
+                                        className="w-fit"
+                                        onClick={() => setRetryCount((c) => c + 1)}
+                                    >
+                                        <RotateCw className="size-3 mr-1" />
+                                        Retry
+                                    </Button>
+                                </div>
                             )
                         ) : loading ? (
                             <div className="flex min-h-0 flex-1 items-center justify-center text-xs text-muted-foreground">Rendering…</div>
diff --git a/src/lib/configTypes.ts b/src/lib/configTypes.ts
index 2096782..edbc011 100644
--- a/src/lib/configTypes.ts
+++ b/src/lib/configTypes.ts
@@ -33,6 +33,7 @@ export type ConfigType = {
 }
 
 const KROKI_PLANTUML_SVG = '/api/kroki/plantuml/svg'
+const KROKI_TIMEOUT_MS = 15000
 
 const PLANTUML_INSERT_BLOCKS: InsertBlockOrGroup[] = [
   { label: 'Diagram start/end', snippet: '@startuml\n\n@enduml' },
@@ -131,16 +132,36 @@ export const CONFIG_TYPES: ConfigType[] = [
     language: 'plantuml',
     insertBlocks: PLANTUML_INSERT_BLOCKS,
     render: async (content: string) => {
-      const res = await fetch(KROKI_PLANTUML_SVG, {
-        method: 'POST',
-        headers: { 'Content-Type': 'text/plain' },
-        body: content,
-      })
-      if (!res.ok) {
-        const err = await res.text()
-        throw new Error(res.status === 400 ? err || 'Invalid PlantUML' : `Kroki error: ${res.status}`)
+      const controller = new AbortController()
+      const timeoutId = setTimeout(() => controller.abort(), KROKI_TIMEOUT_MS)
+      try {
+        const res = await fetch(KROKI_PLANTUML_SVG, {
+          method: 'POST',
+          headers: { 'Content-Type': 'text/plain' },
+          body: content,
+          signal: controller.signal,
+        })
+        clearTimeout(timeoutId)
+        if (!res.ok) {
+          const err = await res.text()
+          if (res.status >= 500) {
+            throw new Error('Diagram service unavailable. Try again later.')
+          }
+          throw new Error(res.status === 400 ? err || 'Invalid PlantUML' : `Kroki error: ${res.status}`)
+        }
+        return res.text()
+      } catch (err: unknown) {
+        clearTimeout(timeoutId)
+        if (err instanceof Error) {
+          if (err.name === 'AbortError') {
+            throw new Error('Diagram request timed out. The service may be slow or unavailable.')
+          }
+          if (err.message.includes('fetch') || err.message.includes('network') || err.message.includes('Failed to fetch')) {
+            throw new Error('Diagram service unavailable. Check your connection or try again later.')
+          }
+        }
+        throw err
       }
-      return res.text()
     },
   },
   {