diff --git a/playwright-tests/manual-edits.spec.ts b/playwright-tests/manual-edits.spec.ts
new file mode 100644
index 0000000..19134f6
--- /dev/null
+++ b/playwright-tests/manual-edits.spec.ts
@@ -0,0 +1,80 @@
+import { test, expect } from "@playwright/test"
+
+test("Manual edits test", async ({ page }) => {
+  await page.goto("http://127.0.0.1:5177/editor?snippet_id=snippet_5")
+  await page.waitForLoadState("networkidle")
+
+  const loginButton = page.getByRole("button", { name: "Fake testuser Login" })
+  await loginButton.waitFor({ state: "visible" })
+  await loginButton.click()
+
+  const combobox = page.getByRole("combobox")
+  await combobox.waitFor({ state: "visible" })
+  await combobox.click()
+
+  const fileOption = page.getByText("manual-edits.json")
+  await fileOption.waitFor({ state: "visible" })
+  await fileOption.click()
+
+  // Wait for file content to load
+  await page.waitForLoadState("networkidle")
+
+  const emptyPlacementsText = page.getByText('"pcb_placements": []')
+  await emptyPlacementsText.waitFor({ state: "visible" })
+  await emptyPlacementsText.click()
+
+  await page.keyboard.press("Control+End")
+  await page.keyboard.down("Shift")
+  await page.keyboard.press("Control+Home")
+  await page.keyboard.up("Shift")
+
+  const pcbPlacementsData = `{
+    "pcb_placements": [
+      {
+        "selector": "U1",
+        "center": {
+          "x": -26.03275345576554,
+          "y": 23.735745797903878
+        },
+        "relative_to": "group_center",
+        "_edit_event_id": "0.5072961258141278"
+      }
+    ],
+    "edit_events": [],
+    "manual_trace_hints": []
+  }`
+
+  await page.keyboard.type(pcbPlacementsData)
+
+  // Wait for Run button and click
+  const runButton = page.getByRole("button", { name: "Run", exact: true })
+  await runButton.waitFor({ state: "visible" })
+  await runButton.click()
+
+  // Wait for any animations/processing after Run
+  await page.waitForLoadState("networkidle")
+
+  // Wait for Save button and click
+  const saveButton = page.getByRole("button", { name: "Save" })
+  await saveButton.waitFor({ state: "visible", timeout: 10000 })
+  await saveButton.click()
+
+  await page.waitForTimeout(1000)
+
+  await expect(page).toHaveScreenshot("editor-manual-edits.png")
+
+  // Navigate to view page
+  await page.goto("http://127.0.0.1:5177/testuser/a555timer-square-wave")
+  await page.waitForLoadState("networkidle")
+
+  const filesLink = page.getByRole("link", { name: "Files" })
+  await filesLink.waitFor({ state: "visible" })
+  await filesLink.click()
+
+  const fileLink = page.getByText("manual-edits.json")
+  await fileLink.waitFor({ state: "visible" })
+  await fileLink.click()
+
+  await page.waitForLoadState("networkidle")
+  await expect(page).toHaveScreenshot("manual-edits-view.png")
+})
diff --git a/playwright-tests/snapshots/manual-edits.spec.ts-editor-manual-edits.png b/playwright-tests/snapshots/manual-edits.spec.ts-editor-manual-edits.png
new file mode 100644
index 0000000..fb2c9c0
Binary files /dev/null and b/playwright-tests/snapshots/manual-edits.spec.ts-editor-manual-edits.png differ
diff --git a/playwright-tests/snapshots/manual-edits.spec.ts-manual-edits-view.png b/playwright-tests/snapshots/manual-edits.spec.ts-manual-edits-view.png
new file mode 100644
index 0000000..7e5ee32
Binary files /dev/null and b/playwright-tests/snapshots/manual-edits.spec.ts-manual-edits-view.png differ
diff --git a/src/components/CodeAndPreview.tsx b/src/components/CodeAndPreview.tsx
index ffb43cd..7724d6d 100644
--- a/src/components/CodeAndPreview.tsx
+++ b/src/components/CodeAndPreview.tsx
@@ -26,6 +26,7 @@ export function CodeAndPreview({ snippet }: Props) {
   const axios = useAxios()
   const isLoggedIn = useGlobalStore((s) => Boolean(s.session))
   const urlParams = useUrlParams()
+  const { toast } = useToast()
   const templateFromUrl = useMemo(
     () => getSnippetTemplate(urlParams.template),
     [],
@@ -41,12 +42,22 @@ export function CodeAndPreview({ snippet }: Props) {
     )
   }, [])
 
-  // Initialize with template or snippet's manual edits if available
-  const [manualEditsFileContent, setManualEditsFileContent] = useState(
-    snippet?.manual_edits_json ??
-      JSON.stringify(manualEditsTemplate, null, 2) ??
-      "",
-  )
+  // Initialize manualEditsFileContent with proper validation
+  const [manualEditsFileContent, setManualEditsFileContent] = useState(() => {
+    try {
+      const initialContent =
+        snippet?.manual_edits_json ??
+        JSON.stringify(manualEditsTemplate, null, 2)
+      // Validate that it's parseable JSON
+      JSON.parse(initialContent)
+      return initialContent
+    } catch (e) {
+      console.warn(
+        "Invalid initial manual edits content, using default template",
+      )
+      return JSON.stringify(manualEditsTemplate, null, 2)
+    }
+  })
   const [code, setCode] = useState(defaultCode ?? "")
   const [dts, setDts] = useState("")
   const [showPreview, setShowPreview] = useState(true)
@@ -62,20 +73,38 @@ export function CodeAndPreview({ snippet }: Props) {
     }
   }, [Boolean(snippet)])
 
-  const { toast } = useToast()
-
+  // Update manual edits when snippet changes, with validation
   useEffect(() => {
     if (snippet?.manual_edits_json) {
-      setManualEditsFileContent(snippet.manual_edits_json)
+      try {
+        JSON.parse(snippet.manual_edits_json)
+        setManualEditsFileContent(snippet.manual_edits_json)
+      } catch (e) {
+        console.warn("Invalid manual edits JSON from snippet")
+        toast({
+          title: "Warning",
+          description:
+            "Invalid manual edits format in snippet. Using default template.",
+          variant: "destructive",
+        })
+        setManualEditsFileContent(JSON.stringify(manualEditsTemplate, null, 2))
+      }
     }
-  }, [Boolean(snippet?.manual_edits_json)])
+  }, [snippet?.manual_edits_json])
 
-  const userImports = useMemo(
-    () => ({
-      "./manual-edits.json": JSON.parse(manualEditsFileContent),
-    }),
-    [manualEditsFileContent],
-  )
+  // Safely parse userImports with error handling
+  const userImports = useMemo(() => {
+    try {
+      return {
+        "./manual-edits.json": JSON.parse(manualEditsFileContent),
+      }
+    } catch (e) {
+      console.warn("Error parsing manual edits for imports, using empty object")
+      return {
+        "./manual-edits.json": {},
+      }
+    }
+  }, [manualEditsFileContent])
 
   const {
     message,
@@ -101,6 +130,14 @@ export function CodeAndPreview({ snippet }: Props) {
   const updateSnippetMutation = useMutation({
     mutationFn: async () => {
       if (!snippet) throw new Error("No snippet to update")
+
+      // Validate manual edits before sending
+      try {
+        JSON.parse(manualEditsFileContent)
+      } catch (e) {
+        throw new Error("Invalid manual edits JSON")
+      }
+
       const response = await axios.post("/snippets/update", {
         snippet_id: snippet.snippet_id,
         code: code,
@@ -125,7 +162,10 @@ export function CodeAndPreview({ snippet }: Props) {
       console.error("Error saving snippet:", error)
       toast({
         title: "Error",
-        description: "Failed to save the snippet. Please try again.",
+        description:
+          error instanceof Error
+            ? error.message
+            : "Failed to save the snippet. Please try again.",
         variant: "destructive",
       })
     },