jarle Bun APIs
Overview of Bun's native APIs available on the Bun global object and built-in modules
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 |
| Shell | $ |
| Bundler | Bun.build |
| File I/O | Bun.file, Bun.write, Bun.stdin, Bun.stdout, Bun.stderr |
| Child Processes | Bun.spawn, Bun.spawnSync |
| TCP Sockets | Bun.listen, Bun.connect |
| UDP Sockets | Bun.udpSocket |
| WebSockets | new WebSocket() (client), Bun.serve (server) |
| Transpiler | Bun.Transpiler |
| Routing | Bun.FileSystemRouter |
| Streaming HTML | HTMLRewriter |
| Hashing | Bun.password, Bun.hash, Bun.CryptoHasher, Bun.sha |
| SQLite | bun:sqlite |
| PostgreSQL Client | Bun.SQL, Bun.sql |
| Redis (Valkey) Client | Bun.RedisClient, Bun.redis |
| FFI (Foreign Function Interface) | bun:ffi |
| DNS | Bun.dns.lookup, Bun.dns.prefetch, Bun.dns.getCacheStats |
| Testing | bun:test |
| Workers | new Worker() |
| Module Loaders | Bun.plugin |
| Glob | Bun.Glob |
| Cookies | Bun.Cookie, Bun.CookieMap |
| Node-API | Node-API |
import.meta |
import.meta |
| Utilities | Bun.version, Bun.revision, Bun.env, Bun.main |
| Sleep & Timing | Bun.sleep(), Bun.sleepSync(), Bun.nanoseconds() |
| Random & UUID | Bun.randomUUIDv7() |
| System & Environment | Bun.which() |
| Comparison & Inspection | Bun.peek(), Bun.deepEquals(), Bun.deepMatch, Bun.inspect() |
| String & Text Processing | Bun.escapeHTML(), Bun.stringWidth(), Bun.indexOfLine |
| URL & Path Utilities | Bun.fileURLToPath(), Bun.pathToFileURL() |
| Compression | Bun.gzipSync(), Bun.gunzipSync(), Bun.deflateSync(), Bun.inflateSync(), Bun.zstdCompressSync(), Bun.zstdDecompressSync(), Bun.zstdCompress(), Bun.zstdDecompress() |
| Stream Processing | Bun.readableStreamTo*(), Bun.readableStreamToBytes(), Bun.readableStreamToBlob(), Bun.readableStreamToFormData(), Bun.readableStreamToJSON(), Bun.readableStreamToArray() |
| Memory & Buffer Management | Bun.ArrayBufferSink, Bun.allocUnsafe, Bun.concatArrayBuffers |
| Module Resolution | Bun.resolveSync() |
| Parsing & Formatting | Bun.semver, Bun.TOML.parse, Bun.markdown, Bun.color |
| Low-level / Internals | Bun.mmap, Bun.gc, Bun.generateHeapSnapshot, bun:jsc |