npmjs.dev

A lightweight in‑browser playground to explore and run npm packages instantly—no local install required. Enter a package in the URL, edit code, run it, and view the package’s README side‑by‑side.

Checkout: https://npmjs.dev/

Or run it locally: npm run dev

This project is an independent experiment and not affiliated with npm, Inc.

Features

• Triple execution engines:
  • QuickJS (WASM) – fast startup, sandboxed
  • Browser (iframe + import map via esm.sh)
  • Cloudflare Dynamic Workers – runtime bundling + edge isolate execution
• Automatic sample code based on URL package
• Live console capture (log / info / warn / error)
• README auto-fetch from unpkg (fallback name variants)
• Zero build step for adding packages—import and run
• Clean React + TypeScript architecture (Vite powered)

For local development:

npm run dev

This starts Wrangler and Vite together. In development, the browser uses same-origin /api/* requests and Vite proxies them to the local Worker automatically.

See docs/cloudflare-dynamic-workers.md for the design notes, tradeoffs, and rollout details.

License

MIT