diff --git a/compiler/apps/playground/components/Editor/ConfigEditor.tsx b/compiler/apps/playground/components/Editor/ConfigEditor.tsx
index e78ff35666b0..87db6d535db2 100644
--- a/compiler/apps/playground/components/Editor/ConfigEditor.tsx
+++ b/compiler/apps/playground/components/Editor/ConfigEditor.tsx
@@ -5,8 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import MonacoEditor, {loader, type Monaco} from '@monaco-editor/react';
-import type {editor} from 'monaco-editor';
+import MonacoEditor, { loader, type Monaco } from '@monaco-editor/react';
+import type { editor } from 'monaco-editor';
 import * as monaco from 'monaco-editor';
 import React, {
   useState,
@@ -15,16 +15,16 @@ import React, {
   unstable_addTransitionType as addTransitionType,
   startTransition,
 } from 'react';
-import {Resizable} from 're-resizable';
-import {useStore, useStoreDispatch} from '../StoreContext';
-import {monacoConfigOptions} from './monacoOptions';
-import {IconChevron} from '../Icons/IconChevron';
-import {CONFIG_PANEL_TRANSITION} from '../../lib/transitionTypes';
+import { Resizable } from 're-resizable';
+import { useStore, useStoreDispatch } from '../StoreContext';
+import { monacoConfigOptions } from './monacoOptions';
+import { IconChevron } from '../Icons/IconChevron';
+import { CONFIG_PANEL_TRANSITION } from '../../lib/transitionTypes';
 
 // @ts-expect-error - webpack asset/source loader handles .d.ts files as strings
 import compilerTypeDefs from 'babel-plugin-react-compiler/dist/index.d.ts';
 
-loader.config({monaco});
+loader.config({ monaco });
 
 export default function ConfigEditor({
   formattedAppliedConfig,
@@ -33,7 +33,7 @@ export default function ConfigEditor({
 }): React.ReactElement {
   const [isExpanded, setIsExpanded] = useState(false);
 
-  // TODO: Add back <Activity> after upgrading next.js
+  // TODO: Addhbn back <Activity> after upgrading next.js
   return (
     <>
       <div
@@ -80,7 +80,8 @@ function ExpandedEditor({
 }): React.ReactElement {
   const store = useStore();
   const dispatchStore = useStoreDispatch();
-  const debounceTimerRef = useRef<NodeJS.Timeout | null>(null);
+  // const debounceTimerRef = useRef<NodeJS.Timeout | null>(null);
+  const debounceTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
 
   const handleChange: (value: string | undefined) => void = (
     value: string | undefined,
@@ -126,14 +127,14 @@ function ExpandedEditor({
 
   return (
     <ViewTransition
-      update={{[CONFIG_PANEL_TRANSITION]: 'slide-in', default: 'none'}}>
+      update={{ [CONFIG_PANEL_TRANSITION]: 'slide-in', default: 'none' }}>
       {/* enter={{[CONFIG_PANEL_TRANSITION]: 'slide-in', default: 'none'}}
       exit={{[CONFIG_PANEL_TRANSITION]: 'slide-out', default: 'none'}}> */}
       <Resizable
         minWidth={300}
         maxWidth={600}
-        defaultSize={{width: 350}}
-        enable={{right: true, bottom: false}}>
+        defaultSize={{ width: 350 }}
+        enable={{ right: true, bottom: false }}>
         <div className="bg-blue-10 relative h-full flex flex-col !h-[calc(100vh_-_3.5rem)] border border-gray-300">
           <div
             className="absolute w-8 h-16 bg-blue-10 rounded-r-full flex items-center justify-center z-[2] cursor-pointer border border-l-0 border-gray-300"
@@ -202,7 +203,7 @@ function CollapsedEditor({
   return (
     <div
       className="w-4 !h-[calc(100vh_-_3.5rem)]"
-      style={{position: 'relative'}}>
+      style={{ position: 'relative' }}>
       <div
         className="absolute w-10 h-16 bg-blue-10 hover:translate-x-2 transition-transform rounded-r-full flex items-center justify-center z-[2] cursor-pointer border border-gray-300"
         title="Expand config editor"
diff --git a/compiler/apps/playground/lib/stores/store.ts b/compiler/apps/playground/lib/stores/store.ts
index 6655efa27408..3cabb69d95f5 100644
--- a/compiler/apps/playground/lib/stores/store.ts
+++ b/compiler/apps/playground/lib/stores/store.ts
@@ -10,7 +10,7 @@ import {
   compressToEncodedURIComponent,
   decompressFromEncodedURIComponent,
 } from 'lz-string';
-import {defaultStore, defaultConfig} from '../defaultStore';
+import { defaultStore, defaultConfig } from '../defaultStore';
 
 /**
  * Global Store for Playground
@@ -23,8 +23,18 @@ export interface Store {
 export function encodeStore(store: Store): string {
   return compressToEncodedURIComponent(JSON.stringify(store));
 }
-export function decodeStore(hash: string): any {
-  return JSON.parse(decompressFromEncodedURIComponent(hash));
+export function decodeStore(hash: string): unknown {
+  // The URL hash and localStorage are user-controlled inputs. Be resilient to
+  // malformed/corrupt values so the playground doesn't hard-crash on load.
+  const decompressed = decompressFromEncodedURIComponent(hash);
+  if (decompressed == null) {
+    return null;
+  }
+  try {
+    return JSON.parse(decompressed);
+  } catch {
+    return null;
+  }
 }
 
 /**
@@ -41,11 +51,18 @@ export function saveStore(store: Store): void {
  * - it has a `source` property and is a string
  */
 function isValidStore(raw: unknown): raw is Store {
+  // Validate the required shape while keeping backwards compatibility with
+  // older stored payloads.
   return (
     raw != null &&
     typeof raw == 'object' &&
     'source' in raw &&
-    typeof raw['source'] === 'string'
+    // typeof raw['source'] === 'string'
+    typeof (raw as Record<string, unknown>)['source'] === 'string' &&
+    (!('config' in raw) ||
+      typeof (raw as Record<string, unknown>)['config'] === 'string') &&
+    (!('showInternals' in raw) ||
+      typeof (raw as Record<string, unknown>)['showInternals'] === 'boolean')
   );
 }
 
@@ -64,10 +81,16 @@ export function initStoreFromUrlOrLocalStorage(): Store {
    */
   if (!encodedSource) return defaultStore;
 
-  const raw: any = decodeStore(encodedSource);
-
+  // const raw: any = decodeStore(encodedSource);
+  const raw = decodeStore(encodedSource);
   invariant(isValidStore(raw), 'Invalid Store');
 
+  // If the decoded data is invalid, treat it as if there was no saved store.
+  // This avoids breaking the playground when someone shares a malformed URL.
+  if (!isValidStore(raw)) {
+    return defaultStore;
+  }
+
   // Make sure all properties are populated
   return {
     source: raw.source,