Bun implements a set of native APIs on the Bun global object and through a number of built-in modules. These APIs are heavily optimized and represent the canonical "Bun-native" way to implement some common functionality.
Bun strives to implement standard Web APIs wherever possible. Bun introduces new APIs primarily for server-side tasks where no standard exists, such as file I/O and starting an HTTP server. In these cases, Bun's approach still builds atop standard APIs like Blob, URL, and Request.
Bun.serve({
fetch(req: Request) {
return new Response("Success!");
},
});
Click the link in the right column to jump to the associated documentation.
| Topic | APIs |
|---|---|
| HTTP server | Bun.serve |
| Bundler | Bun.build |
| File I/O | Bun.file Bun.write |
| Child processes | Bun.spawn Bun.spawnSync |
| TCP | Bun.listen Bun.connect |
| Transpiler | Bun.Transpiler |
| Routing | Bun.FileSystemRouter |
| Streaming HTML Transformations | HTMLRewriter |
| Hashing | Bun.hash Bun.CryptoHasher |
| import.meta | import.meta |
| SQLite | bun:sqlite |
| FFI | bun:ffi |
| Testing | bun:test |
| Node-API | Node-API |
| Glob | Bun.Glob |
| Utilities | Bun.version Bun.revision Bun.env Bun.main Bun.sleep() Bun.sleepSync() Bun.which() Bun.peek() Bun.openInEditor() Bun.deepEquals() Bun.escapeHTML() Bun.fileURLToPath() Bun.pathToFileURL() Bun.gzipSync() Bun.gunzipSync() Bun.deflateSync() Bun.inflateSync() Bun.inspect() Bun.nanoseconds() Bun.readableStreamTo*() Bun.resolveSync() |