UnJS

UnJS is a collection of 63 open source JavaScript packages designed to be runtime-agnostic, working identically across Node.js, Bun, Deno, Cloudflare Workers, Vercel Edge, and browser environments. The ecosystem follows the UNIX philosophy of small, single-purpose tools that compose into larger systems, and collectively accumulates over 421 million monthly downloads on npm with 49,000 GitHub stars. The project is maintained by Pooya Parsa, known in the community as pi0, and serves as the foundational layer beneath major frameworks including Nuxt, Nitro, H3, and Vite plugins. Notable packages include Nitro, a server engine that compiles web applications into deployable artifacts for over 15 hosting platforms; Citty, a command-line argument parser and builder with automatic help generation; Consola, a structured logging library with tag-based filtering and Unicode spinners; DestR, a secure JSON parser that prevents prototype pollution attacks; ofetch, a fetch wrapper with retry logic and error normalization across Node and browser runtimes; Unbuild, a bundling tool that produces ESM, CJS, and type declaration outputs from a single configuration; and Changelogen, a conventional commits changelog generator. Each package is independently versioned and published, with zero cross-dependencies between siblings wherever possible, ensuring that adopting one utility does not pull in unnecessary code. The ecosystem enforces consistent coding conventions, error handling patterns, and API ergonomics across all 63 packages, creating a predictable developer experience. UnJS packages are used by millions of developers indirectly through Nuxt, Storyblok, Poimandres, and other ecosystem consumers.