🔐 Secure Code Sandbox
✅ Isolated iframe + Web Worker | No external calls | 100% client‑side
🧼 Clean, private & safe
Most online code editors track your activity, show ads, or require login. This one is different: everything runs right inside your browser, and nothing is ever uploaded.
- Real Web Worker isolation – your JavaScript cannot access the main page, cookies, localStorage, or make network requests.
- Sandboxed iframe – even if the HTML contains malicious scripts, they can’t break out.
- No signup, no ads, no trackers – just open and start coding.
- Mobile friendly & lightweight – works great on phones and slow connections.
- DOMPurify sanitization – blocks XSS attacks automatically.
Perfect for learning, testing snippets, or sharing code without fear.
Have you ever pasted untrusted JavaScript into a normal editor? Risky. This tool runs your JS inside a separate Worker thread that has no DOM access. The only way to interact with the preview is through a special update(selector, value) function – completely safe.
Other big playgrounds (CodePen, JSFiddle) run your code in the same context as their UI, which can lead to security issues. Here, we prioritise your privacy and safety. Plus, the interface is dead simple – no unnecessary buttons, no clutter.
SEO bonus: Because the page loads instantly and keeps users engaged (testing code), search engines rank it higher. That’s why this tool post is built to perform.
| Feature | Our Tool | CodePen | JSFiddle | JS Bin |
|---|---|---|---|---|
| 🔐 No account needed | ✅ Yes | ❌ Required to save | ✅ Optional | ✅ Optional |
| 🛡️ Real Worker isolation | ✅ Yes | ❌ No | ❌ No | ❌ No |
| 🚫 No tracking / ads | ✅ Yes | ❌ Has ads & analytics | ❌ 3rd party scripts | ⚠️ Some tracking |
| 📱 Truly mobile friendly | ✅ Lightweight | ⚠️ Cluttered | ⚠️ Medium | ✅ Decent |
| 💯 Free forever | ✅ Completely free | ❌ Pro features | ⚠️ Limited free | ✅ Free (but limited) |
🎯 The verdict: if you value privacy, security, and simplicity, this tool is your best choice.
Explore other handy utilities – all made with the same no‑tracking, no‑nonsense approach:
update() function?
update(selector, value) to change the text of any element inside the preview iframe. Example: update("#demo", "Hello"). This is the only bridge between the worker and the preview – keeping everything isolated.