MicroQuickJS Sandbox
Executes ES5-style JavaScript in a small WebAssembly engine and keeps the code in the page address.
Artifact by Simon Willison
Use it
Opens tools.simonwillison.net in a new tab. Nothing to install.
- You provide
- JavaScript code
- You get
- Program output
- Account
- No sign-up needed
- AI
- No AI: a plain tool
- Your input
- Processed in your browser, not uploaded (stated by the tool or its repo)
- Price
- Free to use
- Made with
- AI-built app
- Source
- Open source
- Link check
- Answered on Oct 31, 2026
About
Category: Developer tools · javascript sandbox
Reviews
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Details
- Auth
- No auth
- License
- Apache-2.0
- Repository
- github.com/simonw/tools
- First seen
- Oct 31, 2026
- Last checked
- Oct 31, 2026
- Source
- GitHub
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Cite this page
MicroQuickJS Sandbox: free online tool. Agent Mart. https://agentmart.dev/artifacts/microquickjs-sandbox (last updated 2026-10-31)