diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..a17a7af
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,240 @@
+import EventEmitter from 'bare-events'
+import Buffer, { BufferEncoding } from 'bare-buffer'
+
+// duplicated from 'bare-events'
+declare interface EventMap {
+  [event: string | symbol]: unknown[]
+}
+
+type StreamOptions = {
+  destroy?: Stream['_destroy']
+  eagerOpen?: boolean
+  open?: Stream['_open']
+  predestroy?: Stream['_predestroy']
+  signal?: AbortSignal
+}
+
+declare interface Stream<M extends EventMap = EventMap>
+  extends EventEmitter<M> {
+  _open(cb: (err?: Error | null) => void): void
+  _destroy: (
+    this: this,
+    err: Error | null,
+    cb: (err?: Error | null) => void
+  ) => void
+  _predestroy(): void
+
+  get readable(): boolean
+  get writable(): boolean
+  get destroyed(): boolean
+  get destroying(): boolean
+
+  destroy(err?: Error | null): void
+}
+
+declare class Stream {
+  constructor(opts?: StreamOptions)
+}
+
+type ReadableOptions = {
+  byteLength?: (data: unknown) => number
+  byteLengthReadable?: (data: unknown) => number
+  encoding?: BufferEncoding
+  highWaterMark?: number
+  map?: (data: unknown) => unknown
+  mapReadable?: (data: unknown) => unknown
+  read?: Readable['_read']
+} & StreamOptions
+
+declare interface Readable<T = Buffer | string>
+  extends Stream<{
+    data: [data: T | null]
+    close: []
+    end: []
+    error: [err: Error]
+    readable: []
+    piping: [dest: unknown]
+  }> {
+  _read(this: this, size: number): void
+
+  push(chunk: T | null, encoding?: BufferEncoding): boolean
+
+  unshift(chunk: T | null, encoding?: BufferEncoding): boolean
+
+  read(): T | null
+
+  resume(): this
+  pause(): this
+
+  pipe<A extends Writable | Duplex>(dest: A, cb?: (err: Error) => void): A
+
+  setEncoding(encoding: BufferEncoding): void
+
+  [Symbol.asyncIterator](): AsyncIterator<T>
+}
+
+declare class Readable {
+  static from(data: unknown | unknown[], opts?: ReadableOptions): Readable
+
+  static isBackpressured(rs: Readable): boolean
+  static isPaused(rs: Readable): boolean
+
+  constructor(opts?: ReadableOptions)
+}
+
+type WritableOptions = {
+  final?: Writable['_final']
+  mapWritable?: (data: unknown) => unknown
+  write?: Writable['_write']
+  writev?: Writable['_writev']
+} & StreamOptions
+
+declare interface Writable<T = Buffer | string>
+  extends Stream<{
+    drain: []
+    finish: []
+    close: []
+    error: [err: Error]
+    pipe: [src: Readable]
+  }> {
+  readonly destroyed: boolean
+
+  _writev(this: this, batch: T[], cb: (err?: Error | null) => void): void
+  _write(
+    this: this,
+    data: T,
+    encoding: BufferEncoding,
+    cb: (err?: Error | null) => void
+  ): void
+  _final(this: this, cb: (err?: Error | null) => void): void
+
+  write(chunk: T, encoding?: BufferEncoding, cb?: () => void): boolean
+  write(chunk: T, cb?: () => void): boolean
+
+  end(chunk: T, encoding?: BufferEncoding, cb?: () => void): this
+  end(chunk: T, cb?: () => void): this
+  end(cb?: () => void): this
+
+  cork(): void
+  uncork(): void
+}
+
+declare class Writable {
+  static isBackpressured(ws: Writable): Promise<boolean>
+  static drained(ws: Writable): Promise<boolean>
+
+  constructor(opts?: WritableOptions)
+}
+
+type DuplexOptions = ReadableOptions & WritableOptions
+
+declare interface Duplex<T = Buffer | string>
+  extends Stream<{
+    close: []
+    data: [data: T | null]
+    drain: []
+    end: []
+    error: [err: Error]
+    finish: []
+    pipe: [src: Readable]
+    piping: [dest: unknown]
+    readable: []
+  }> {
+  _read(this: this, size: number): void
+  _writev(this: this, batch: T[], cb: (err?: Error | null) => void): void
+  _write(this: this, data: T, cb: (err?: Error | null) => void): void
+  _final(this: this, cb: (err?: Error | null) => void): void
+
+  write(chunk: T, encoding?: BufferEncoding, cb?: () => void): boolean
+  write(chunk: T, cb?: () => void): boolean
+
+  end(chunk: T, encoding?: BufferEncoding, cb?: () => void): this
+  end(chunk: T, cb?: () => void): this
+  end(cb?: () => void): this
+
+  push(chunk: T | null, encoding?: BufferEncoding): boolean
+  unshift(chunk: T | null, encoding?: BufferEncoding): boolean
+
+  read(): T | null
+
+  resume(): this
+  pause(): this
+
+  pipe<A extends Stream>(dest: A, cb?: (err: Error) => void): A
+
+  setEncoding(encoding: BufferEncoding): void
+
+  cork(): void
+  uncork(): void
+
+  [Symbol.asyncIterator](): AsyncIterator<T>
+}
+
+declare class Duplex {
+  constructor(opts?: DuplexOptions)
+}
+
+type TransformOptions = {
+  flush?: Transform['_flush']
+  transform?: Transform['_transform']
+} & DuplexOptions
+
+declare interface Transform<T = Buffer | string> extends Duplex {
+  _transform(
+    this: this,
+    data: T,
+    encoding: BufferEncoding,
+    cb: (err?: Error | null) => void
+  ): void
+  _flush(cb: (this: this, err: Error | null) => void): void
+}
+
+declare class Transform {
+  constructor(opts?: TransformOptions)
+}
+
+declare class Pipeline {
+  constructor(src: Stream, dst: Stream, cb: (err?: Error | null) => void)
+
+  finished(): void
+
+  done(stream: Stream, err: Error): void
+}
+
+declare namespace Stream {
+  export {
+    Pipeline,
+    Stream,
+    Readable,
+    Writable,
+    Duplex,
+    Transform,
+    Transform as PassThrough
+  }
+
+  export function finished(
+    stream: Stream,
+    opts: { cleanup?: boolean },
+    cb: (err?: Error | null) => void
+  ): () => void
+
+  export function finished(
+    stream: Stream,
+    cb: (err?: Error | null) => void
+  ): () => void
+
+  export function isStream(stream: unknown): stream is Stream
+
+  export function isEnded(stream: Stream): boolean
+
+  export function isFinished(stream: Stream): boolean
+
+  export function isDisturbed(stream: Stream): boolean
+
+  export function getStreamError(
+    stream: Stream,
+    opts?: { all?: boolean }
+  ): Error | null
+}
+
+export = Stream
diff --git a/package.json b/package.json
index 7493b73..1c3fec8 100644
--- a/package.json
+++ b/package.json
@@ -3,7 +3,10 @@
   "version": "2.6.1",
   "description": "Streaming data for JavaScript",
   "exports": {
-    ".": "./index.js",
+    ".": {
+      "types": "./index.d.ts",
+      "default": "./index.js"
+    },
     "./package": "./package.json",
     "./promises": "./promises.js",
     "./web": "./web.js",
@@ -11,6 +14,7 @@
   },
   "files": [
     "index.js",
+    "index.d.ts",
     "promises.js",
     "web.js",
     "global.js"
@@ -32,8 +36,14 @@
     "streamx": "^2.21.0"
   },
   "devDependencies": {
+    "bare-buffer": "^2.7.1",
+    "bare-events": "^2.5.3",
     "brittle": "^3.5.2",
     "prettier": "^3.3.3",
     "prettier-config-standard": "^7.0.0"
+  },
+  "peerDependencies": {
+    "bare-buffer": "*",
+    "bare-events": "*"
   }
 }