Bun aims for complete Node.js API compatibility. Most `npm` packages intended for `Node.js` environments will work with Bun out of the box; the best way to know for certain is to try it.

This page is updated regularly to reflect compatibility status of the latest version of Bun. The information below reflects Bun's compatibility with _Node.js v20_. If you run into any bugs with a particular package, please [open an issue](https://bun.sh/issues). Opening issues for compatibility bugs helps us prioritize what to work on next.

## Built-in modules

### [`node:assert`](https://nodejs.org/api/assert.html)

🟡 Missing `doesNotMatch`

### [`node:async_hooks`](https://nodejs.org/api/async_hooks.html)

🟡 Only `AsyncLocalStorage`, and `AsyncResource` are implemented. `AsyncResource` is missing `bind`.

### [`node:buffer`](https://nodejs.org/api/buffer.html)

🟢 Fully implemented.

### [`node:child_process`](https://nodejs.org/api/child_process.html)

🟡 Missing `Stream` stdio, `proc.gid` `proc.uid`. IPC has partial support and only current only works with other `bun` processes.

### [`node:cluster`](https://nodejs.org/api/cluster.html)

🔴 Not implemented.

### [`node:console`](https://nodejs.org/api/console.html)

🟢 Fully implemented.

### [`node:crypto`](https://nodejs.org/api/crypto.html)

🟡 Missing `Certificate` `ECDH` `X509Certificate` `checkPrime` `checkPrimeSync` `diffieHellman` `generatePrime` `generatePrimeSync` `getCipherInfo` `getFips` `hkdf` `hkdfSync` `secureHeapUsed` `setEngine` `setFips`

Some methods are not optimized yet.

### [`node:dgram`](https://nodejs.org/api/dgram.html)

🔴 Not implemented.

### [`node:diagnostics_channel`](https://nodejs.org/api/diagnostics_channel.html)

🟢 Fully implemented.

### [`node:dns`](https://nodejs.org/api/dns.html)

🟡 Missing `cancel` `setServers` `getDefaultResultOrder`

### [`node:domain`](https://nodejs.org/api/domain.html)

🟡 Missing `Domain` `active`

### [`node:events`](https://nodejs.org/api/events.html)

🟡 Missing `on` `addAbortListener` `getMaxListeners`

### [`node:fs`](https://nodejs.org/api/fs.html)

🟡 Missing `Dir` `fdatasync` `fdatasyncSync` `openAsBlob` `opendir` `opendirSync` `statfs` `statfsSync`. `fs.promises.open` incorrectly returns a file descriptor instead of a `FileHandle`.

### [`node:http`](https://nodejs.org/api/http.html)

🟢 Fully implemented.

### [`node:http2`](https://nodejs.org/api/http2.html)

🔴 Not implemented.

### [`node:https`](https://nodejs.org/api/https.html)

🟢 Fully implemented.

### [`node:inspector`](https://nodejs.org/api/inspector.html)

🔴 Not implemented.

### [`node:module`](https://nodejs.org/api/module.html)

🟢 Missing `runMain` `syncBuiltinESMExports`, `Module#load()`. Attempts to override or patch the module cache will fail.

### [`node:net`](https://nodejs.org/api/net.html)

🟡 Missing `BlockList` `SocketAddress` `Stream` `getDefaultAutoSelectFamily` `getDefaultAutoSelectFamilyAttemptTimeout` `setDefaultAutoSelectFamily` `setDefaultAutoSelectFamilyAttemptTimeout` `Server#ref()` `Server#unref()` `Socket#ref()` `Socket#unref()`.

### [`node:os`](https://nodejs.org/api/os.html)

🟢 Fully implemented.

### [`node:path`](https://nodejs.org/api/path.html)

🟢 Fully implemented.

### [`node:perf_hooks`](https://nodejs.org/api/perf_hooks.html)

🟡 Only `perf_hooks.performance.now()` and `perf_hooks.performance.timeOrigin` are implemented. Missing `Performance` `PerformanceMark` `PerformanceMeasure` `PerformanceObserverEntryList` `PerformanceResourceTiming` `createHistogram` `monitorEventLoopDelay`. It's recommended to use `performance` global instead of `perf_hooks.performance`.

### [`node:process`](https://nodejs.org/api/process.html)

🟡 See [`process`](#process) Global.

### [`node:punycode`](https://nodejs.org/api/punycode.html)

🟢 Fully implemented. _Deprecated by Node.js._

### [`node:querystring`](https://nodejs.org/api/querystring.html)

🟢 Fully implemented.

### [`node:readline`](https://nodejs.org/api/readline.html)

🟢 Fully implemented.

### [`node:repl`](https://nodejs.org/api/repl.html)

🔴 Not implemented.

### [`node:stream`](https://nodejs.org/api/stream.html)

🟡 Missing `getDefaultHighWaterMark` `setDefaultHighWaterMark`

### [`node:string_decoder`](https://nodejs.org/api/string_decoder.html)

🟢 Fully implemented.

### [`node:sys`](https://nodejs.org/api/util.html)

🟡 See [`node:util`](#node-util).

### [`node:timers`](https://nodejs.org/api/timers.html)

🟢 Recommended to use global `setTimeout`, et. al. instead.

### [`node:tls`](https://nodejs.org/api/tls.html)

🟡 Missing `tls.createSecurePair`.

### [`node:trace_events`](https://nodejs.org/api/tracing.html)

🔴 Not implemented.

### [`node:tty`](https://nodejs.org/api/tty.html)

🟢 Fully implemented.

### [`node:url`](https://nodejs.org/api/url.html)

🟡 Missing `domainToASCII` `domainToUnicode`. It's recommended to use `URL` and `URLSearchParams` globals instead.

### [`node:util`](https://nodejs.org/api/util.html)

🟡 Missing `MIMEParams` `MIMEType` `aborted` `debug` `getSystemErrorMap` `getSystemErrorName` `parseArgs` `transferableAbortController` `transferableAbortSignal` `stripVTControlCharacters`

### [`node:v8`](https://nodejs.org/api/v8.html)

🔴 `serialize` and `deserialize` use JavaScriptCore's wire format instead of V8's. Otherwise, not implemented. For profiling, use [`bun:jsc`](/docs/project/benchmarking#bunjsc) instead.

### [`node:vm`](https://nodejs.org/api/vm.html)

🟡 Core functionality works, but VM modules are not implemented. Missing `createScript`. `ShadowRealm` can be used.

### [`node:wasi`](https://nodejs.org/api/wasi.html)

🟡 Partially implemented.

### [`node:worker_threads`](https://nodejs.org/api/worker_threads.html)

🟡 `Worker` doesn't support the following options: `eval` `argv` `execArgv` `stdin` `stdout` `stderr` `trackedUnmanagedFds` `resourceLimits`. Missing `markAsUntransferable` `moveMessagePortToContext` `getHeapSnapshot`.

### [`node:zlib`](https://nodejs.org/api/zlib.html)

🟡 Missing `BrotliCompress` `BrotliDecompress` `brotliCompressSync` `brotliDecompress` `brotliDecompressSync` `createBrotliCompress` `createBrotliDecompress`. Unoptimized.

## Globals

The table below lists all globals implemented by Node.js and Bun's current compatibility status.

### [`AbortController`](https://developer.mozilla.org/en-US/docs/Web/API/AbortController)

🟢 Fully implemented.

### [`AbortSignal`](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal)

🟢 Fully implemented.

### [`Blob`](https://developer.mozilla.org/en-US/docs/Web/API/Blob)

🟢 Fully implemented.

### [`Buffer`](https://nodejs.org/api/buffer.html#class-buffer)

🟡 Incomplete implementation of `base64` and `base64url` encodings.

### [`ByteLengthQueuingStrategy`](https://developer.mozilla.org/en-US/docs/Web/API/ByteLengthQueuingStrategy)

🟢 Fully implemented.

### [`__dirname`](https://nodejs.org/api/globals.html#__dirname)

🟢 Fully implemented.

### [`__filename`](https://nodejs.org/api/globals.html#__filename)

🟢 Fully implemented.

### [`atob()`](https://developer.mozilla.org/en-US/docs/Web/API/atob)

🟢 Fully implemented.

### [`BroadcastChannel`](https://developer.mozilla.org/en-US/docs/Web/API/BroadcastChannel)

🟢 Fully implemented.

### [`btoa()`](https://developer.mozilla.org/en-US/docs/Web/API/btoa)

🟢 Fully implemented.

### [`clearImmediate()`](https://developer.mozilla.org/en-US/docs/Web/API/Window/clearImmediate)

🟢 Fully implemented.

### [`clearInterval()`](https://developer.mozilla.org/en-US/docs/Web/API/Window/clearInterval)

🟢 Fully implemented.

### [`clearTimeout()`](https://developer.mozilla.org/en-US/docs/Web/API/Window/clearTimeout)

🟢 Fully implemented.

### [`CompressionStream`](https://developer.mozilla.org/en-US/docs/Web/API/CompressionStream)

🔴 Not implemented.

### [`console`](https://developer.mozilla.org/en-US/docs/Web/API/console)

🟢 Fully implemented.

### [`CountQueuingStrategy`](https://developer.mozilla.org/en-US/docs/Web/API/CountQueuingStrategy)

🟢 Fully implemented.

### [`Crypto`](https://developer.mozilla.org/en-US/docs/Web/API/Crypto)

🟢 Fully implemented.

### [`SubtleCrypto (crypto)`](https://developer.mozilla.org/en-US/docs/Web/API/crypto)

🟢 Fully implemented.

### [`CryptoKey`](https://developer.mozilla.org/en-US/docs/Web/API/CryptoKey)

🟢 Fully implemented.

### [`CustomEvent`](https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent)

🟢 Fully implemented.

### [`DecompressionStream`](https://developer.mozilla.org/en-US/docs/Web/API/DecompressionStream)

🔴 Not implemented.

### [`Event`](https://developer.mozilla.org/en-US/docs/Web/API/Event)

🟢 Fully implemented.

### [`EventTarget`](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget)

🟢 Fully implemented.

### [`exports`](https://nodejs.org/api/globals.html#exports)

🟢 Fully implemented.

### [`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/fetch)

🟢 Fully implemented.

### [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData)

🟢 Fully implemented.

### [`global`](https://nodejs.org/api/globals.html#global)

🟢 Implemented. This is an object containing all objects in the global namespace. It's rarely referenced directly, as its contents are available without an additional prefix, e.g. `__dirname` instead of `global.__dirname`.

### [`globalThis`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis)

🟢 Aliases to `global`.

### [`Headers`](https://developer.mozilla.org/en-US/docs/Web/API/Headers)

🟢 Fully implemented.

### [`MessageChannel`](https://developer.mozilla.org/en-US/docs/Web/API/MessageChannel)

🟢 Fully implemented.

### [`MessageEvent`](https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent)

🟢 Fully implemented.

### [`MessagePort`](https://developer.mozilla.org/en-US/docs/Web/API/MessagePort)

🟢 Fully implemented.

### [`module`](https://nodejs.org/api/globals.html#module)

🟢 Fully implemented.

### [`PerformanceEntry`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEntry)

🔴 Not implemented.

### [`PerformanceMark`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceMark)

🔴 Not implemented.

### [`PerformanceMeasure`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceMeasure)

🔴 Not implemented.

### [`PerformanceObserver`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver)

🔴 Not implemented.

### [`PerformanceObserverEntryList`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserverEntryList)

🔴 Not implemented.

### [`PerformanceResourceTiming`](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming)

🔴 Not implemented.

### [`performance`](https://developer.mozilla.org/en-US/docs/Web/API/performance)

🟢 Fully implemented.

### [`process`](https://nodejs.org/api/process.html)

🟡 Missing `domain` `hasUncaughtExceptionCaptureCallback` `initgroups` `report` `resourceUsage` `setUncaughtExceptionCaptureCallback` `setegid` `seteuid` `setgid` `setgroups` `setuid` `allowedNodeEnvironmentFlags` `getActiveResourcesInfo` `setActiveResourcesInfo` `moduleLoadList` `setSourceMapsEnabled` `channel`. `process.binding` is partially implemented.

### [`queueMicrotask()`](https://developer.mozilla.org/en-US/docs/Web/API/queueMicrotask)

🟢 Fully implemented.

### [`ReadableByteStreamController`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableByteStreamController)

🟢 Fully implemented.

### [`ReadableStream`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream)

🟢 Fully implemented.

### [`ReadableStreamBYOBReader`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamBYOBReader)

🔴 Not implemented.

### [`ReadableStreamBYOBRequest`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamBYOBRequest)

🔴 Not implemented.

### [`ReadableStreamDefaultController`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultController)

🟢 Fully implemented.

### [`ReadableStreamDefaultReader`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultReader)

🟢 Fully implemented.

### [`require()`](https://nodejs.org/api/globals.html#require)

🟢 Fully implemented, including [`require.main`](https://nodejs.org/api/modules.html#requiremain), [`require.cache`](https://nodejs.org/api/modules.html#requirecache), [`require.resolve`](https://nodejs.org/api/modules.html#requireresolverequest-options)

### [`Response`](https://developer.mozilla.org/en-US/docs/Web/API/Response)

🟢 Fully implemented.

### [`Request`](https://developer.mozilla.org/en-US/docs/Web/API/Request)

🟢 Fully implemented.

### [`setImmediate()`](https://developer.mozilla.org/en-US/docs/Web/API/Window/setImmediate)

🟢 Fully implemented.

### [`setInterval()`](https://developer.mozilla.org/en-US/docs/Web/API/Window/setInterval)

🟢 Fully implemented.

### [`setTimeout()`](https://developer.mozilla.org/en-US/docs/Web/API/Window/setTimeout)

🟢 Fully implemented.

### [`structuredClone()`](https://developer.mozilla.org/en-US/docs/Web/API/structuredClone)

🟢 Fully implemented.

### [`SubtleCrypto`](https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto)

🟢 Fully implemented.

### [`DOMException`](https://developer.mozilla.org/en-US/docs/Web/API/DOMException)

🟢 Fully implemented.

### [`TextDecoder`](https://developer.mozilla.org/en-US/docs/Web/API/TextDecoder)

🟢 Fully implemented.

### [`TextDecoderStream`](https://developer.mozilla.org/en-US/docs/Web/API/TextDecoderStream)

🔴 Not implemented.

### [`TextEncoder`](https://developer.mozilla.org/en-US/docs/Web/API/TextEncoder)

🟢 Fully implemented.

### [`TextEncoderStream`](https://developer.mozilla.org/en-US/docs/Web/API/TextEncoderStream)

🔴 Not implemented.

### [`TransformStream`](https://developer.mozilla.org/en-US/docs/Web/API/TransformStream)

🟢 Fully implemented.

### [`TransformStreamDefaultController`](https://developer.mozilla.org/en-US/docs/Web/API/TransformStreamDefaultController)

🟢 Fully implemented.

### [`URL`](https://developer.mozilla.org/en-US/docs/Web/API/URL)

🟢 Fully implemented.

### [`URLSearchParams`](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams)

🟢 Fully implemented.

### [`WebAssembly`](https://nodejs.org/api/globals.html#webassembly)

🟢 Fully implemented.

### [`WritableStream`](https://developer.mozilla.org/en-US/docs/Web/API/WritableStream)

🟢 Fully implemented.

### [`WritableStreamDefaultController`](https://developer.mozilla.org/en-US/docs/Web/API/WritableStreamDefaultController)

🟢 Fully implemented.

### [`WritableStreamDefaultWriter`](https://developer.mozilla.org/en-US/docs/Web/API/WritableStreamDefaultWriter)

🟢 Fully implemented.