WRITE. TRY. KEEP BUILDING.

Your browser. Your code.

A focused code editor for more than 140 languages. Syntax highlighting, line numbers, bracket matching, undo and downloads, with no account required.

Tab indents. Press Escape, then Tab to move keyboard focus out of the editor. Drafts stay in this tab while you switch languages and disappear when you leave or reload.

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What runs here?

Run locally

JavaScript and TypeScript run in a fresh, isolated worker. TypeScript types are stripped for execution; this is not a full type checker. Top-level await works. Use console.log to see results.

Explore data

SQL and SQLite use an in-memory SQLite database that resets for every run. JSON validates and formats locally. SQLite downloads its self-hosted runtime on first use.

Preview the web

HTML and CSS have a scriptless, sandboxed preview. External resources, navigation permissions and forms are restricted. Run standalone JavaScript with the JavaScript option.

Edit other languages

C#, Java, Python, C, C++, Rust, Go, PHP, Ruby, Swift, Kotlin and many more have highlighting and downloads. Compile or run those files using the appropriate runtime on your device.

Small experiments, clear limits.

Code stays in browser memory and is never automatically uploaded or saved. Runnable snippets cannot access this site’s cookies or storage, and their network requests are blocked. Each worker is stopped after eight seconds; you can stop it sooner. Output is limited to 200 lines and 2,000 characters per line, and code is limited to 100,000 characters per run.

This is a scratchpad for standalone snippets. Node.js APIs, package installation, interactive terminal input and project builds are not available. Keep a copy of work you want to save before closing the tab. CPU and memory use still depend on your device.