Runs entirely in your browser

Playground

Write JavaScript or Python and run it instantly — no signup, no server, no data leaving your device. JavaScript executes in a sandboxed frame; Python runs on a real interpreter compiled to WebAssembly (Pyodide). ⌘/Ctrl + Enter to run.

Sandboxed. JS runs in an isolated frame with no access to this site's data, cookies, or storage.

Works offline. Once loaded, JavaScript needs zero network. Python stays cached after its first run.

5-second limit. Scripts that hang or infinite-loop are stopped automatically.