diff --git a/github-webhook-handler.d.ts b/github-webhook-handler.d.ts
deleted file mode 100644
index 123649e..0000000
--- a/github-webhook-handler.d.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-/// <reference types="node" />
-
-import { IncomingMessage, ServerResponse } from 'node:http'
-import { EventEmitter } from 'node:events'
-
-interface CreateHandlerOptions {
-  path: string
-  secret: string
-  events?: string | string[]
-}
-
-interface Handler extends EventEmitter {
-  (req: IncomingMessage, res: ServerResponse, callback: (err?: Error) => void): void
-  sign(data: string | Buffer): string
-  verify(signature: string, data: string | Buffer): boolean
-}
-
-declare function createHandler (options: CreateHandlerOptions | CreateHandlerOptions[]): Handler
-
-export default createHandler
diff --git a/github-webhook-handler.js b/github-webhook-handler.js
index 6bbd6e0..0754419 100644
--- a/github-webhook-handler.js
+++ b/github-webhook-handler.js
@@ -2,6 +2,29 @@ import { EventEmitter } from 'node:events'
 import crypto from 'node:crypto'
 import bl from 'bl'
 
+/**
+ * @typedef {Object} CreateHandlerOptions
+ * @property {string} path
+ * @property {string} secret
+ * @property {string | string[]} [events]
+ */
+
+/**
+ * @typedef {Object} WebhookEvent
+ * @property {string} event - The event type (e.g. 'push', 'issues')
+ * @property {string} id - The delivery ID from X-Github-Delivery header
+ * @property {any} payload - The parsed JSON payload
+ * @property {string} [protocol] - The request protocol
+ * @property {string} [host] - The request host header
+ * @property {string} url - The request URL
+ * @property {string} path - The matched handler path
+ */
+
+/**
+ * @param {string} url
+ * @param {CreateHandlerOptions | CreateHandlerOptions[]} arr
+ * @returns {CreateHandlerOptions}
+ */
 function findHandler (url, arr) {
   if (!Array.isArray(arr)) {
     return arr
@@ -17,6 +40,9 @@ function findHandler (url, arr) {
   return ret
 }
 
+/**
+ * @param {CreateHandlerOptions} options
+ */
 function checkType (options) {
   if (typeof options !== 'object') {
     throw new TypeError('must provide an options object')
@@ -31,7 +57,12 @@ function checkType (options) {
   }
 }
 
+/**
+ * @param {CreateHandlerOptions | CreateHandlerOptions[]} initOptions
+ * @returns {EventEmitter & {(req: import('node:http').IncomingMessage, res: import('node:http').ServerResponse, callback: (err?: Error) => void): void, sign(data: string | Buffer): string, verify(signature: string, data: string | Buffer): boolean}}
+ */
 function create (initOptions) {
+  /** @type {CreateHandlerOptions} */
   let options
   if (Array.isArray(initOptions)) {
     for (let i = 0; i < initOptions.length; i++) {
@@ -41,18 +72,30 @@ function create (initOptions) {
     checkType(initOptions)
   }
 
+  // @ts-ignore - handler is a callable EventEmitter via setPrototypeOf
   Object.setPrototypeOf(handler, EventEmitter.prototype)
+  // @ts-ignore
   EventEmitter.call(handler)
 
   handler.sign = sign
   handler.verify = verify
 
+  // @ts-ignore
   return handler
 
+  /**
+   * @param {string | Buffer} data
+   * @returns {string}
+   */
   function sign (data) {
     return `sha1=${crypto.createHmac('sha1', options.secret).update(data).digest('hex')}`
   }
 
+  /**
+   * @param {string} signature
+   * @param {string | Buffer} data
+   * @returns {boolean}
+   */
   function verify (signature, data) {
     const sig = Buffer.from(signature)
     const signed = Buffer.from(sign(data))
@@ -62,10 +105,16 @@ function create (initOptions) {
     return crypto.timingSafeEqual(sig, signed)
   }
 
+  /**
+   * @param {import('node:http').IncomingMessage} req
+   * @param {import('node:http').ServerResponse} res
+   * @param {(err?: Error) => void} callback
+   */
   function handler (req, res, callback) {
+    /** @type {string[] | undefined} */
     let events
 
-    options = findHandler(req.url, initOptions)
+    options = findHandler(/** @type {string} */ (req.url), initOptions)
 
     if (typeof options.events === 'string' && options.events !== '*') {
       events = [options.events]
@@ -77,12 +126,16 @@ function create (initOptions) {
       return callback()
     }
 
+    /**
+     * @param {string} msg
+     */
     function hasError (msg) {
       res.writeHead(400, { 'content-type': 'application/json' })
       res.end(JSON.stringify({ error: msg }))
 
       const err = new Error(msg)
 
+      // @ts-ignore - handler has EventEmitter prototype
       handler.emit('error', err, req)
       callback(err)
     }
@@ -103,7 +156,7 @@ function create (initOptions) {
       return hasError('No X-Github-Delivery found on request')
     }
 
-    if (events && events.indexOf(event) === -1) {
+    if (events && events.indexOf(/** @type {string} */ (event)) === -1) {
       return hasError('X-Github-Event is not acceptable')
     }
 
@@ -114,14 +167,14 @@ function create (initOptions) {
 
       let obj
 
-      if (!verify(sig, data)) {
+      if (!verify(/** @type {string} */ (sig), data)) {
         return hasError('X-Hub-Signature does not match blob signature')
       }
 
       try {
         obj = JSON.parse(data.toString())
       } catch (e) {
-        return hasError(e)
+        return hasError(/** @type {Error} */ (e).message)
       }
 
       res.writeHead(200, { 'content-type': 'application/json' })
@@ -131,13 +184,15 @@ function create (initOptions) {
         event,
         id,
         payload: obj,
-        protocol: req.protocol,
+        protocol: /** @type {any} */ (req).protocol,
         host: req.headers.host,
         url: req.url,
         path: options.path
       }
 
+      // @ts-ignore - handler has EventEmitter prototype
       handler.emit(event, emitData)
+      // @ts-ignore - handler has EventEmitter prototype
       handler.emit('*', emitData)
     }))
   }
diff --git a/package.json b/package.json
index a83a894..390454e 100644
--- a/package.json
+++ b/package.json
@@ -4,14 +4,21 @@
   "description": "Web handler / middleware for processing GitHub Webhooks",
   "type": "module",
   "main": "github-webhook-handler.js",
-  "exports": "./github-webhook-handler.js",
-  "types": "github-webhook-handler.d.ts",
+  "exports": {
+    ".": {
+      "import": "./github-webhook-handler.js",
+      "types": "./types/github-webhook-handler.d.ts"
+    }
+  },
+  "types": "types/github-webhook-handler.d.ts",
   "engines": {
     "node": ">=20"
   },
   "scripts": {
     "lint": "standard",
-    "build": "true",
+    "build": "npm run build:types",
+    "build:types": "tsc --build",
+    "prepublishOnly": "npm run build",
     "test:unit": "node --test test.js",
     "test": "npm run lint && npm run test:unit"
   },
@@ -35,9 +42,11 @@
     "@semantic-release/github": "^12.0.2",
     "@semantic-release/npm": "^13.1.3",
     "@semantic-release/release-notes-generator": "^14.1.0",
+    "@types/node": "^25.0.10",
     "conventional-changelog-conventionalcommits": "^9.1.0",
     "semantic-release": "^25.0.2",
-    "standard": "^17.1.2"
+    "standard": "^17.1.2",
+    "typescript": "^5.9.3"
   },
   "release": {
     "branches": [
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..4930d18
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,37 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "checkJs": true,
+    "forceConsistentCasingInFileNames": true,
+    "noImplicitReturns": false,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "strictFunctionTypes": false,
+    "strictNullChecks": true,
+    "strictPropertyInitialization": true,
+    "strictBindCallApply": true,
+    "strict": true,
+    "alwaysStrict": true,
+    "esModuleInterop": true,
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "declaration": true,
+    "declarationMap": true,
+    "outDir": "types",
+    "skipLibCheck": true,
+    "stripInternal": true,
+    "resolveJsonModule": true,
+    "baseUrl": ".",
+    "emitDeclarationOnly": true,
+    "paths": {
+      "github-webhook-handler": ["github-webhook-handler.js"]
+    }
+  },
+  "include": ["github-webhook-handler.js"],
+  "exclude": ["node_modules"],
+  "compileOnSave": false
+}
diff --git a/types/github-webhook-handler.d.ts b/types/github-webhook-handler.d.ts
new file mode 100644
index 0000000..77e985c
--- /dev/null
+++ b/types/github-webhook-handler.d.ts
@@ -0,0 +1,47 @@
+export default create;
+export type CreateHandlerOptions = {
+    path: string;
+    secret: string;
+    events?: string | string[] | undefined;
+};
+export type WebhookEvent = {
+    /**
+     * - The event type (e.g. 'push', 'issues')
+     */
+    event: string;
+    /**
+     * - The delivery ID from X-Github-Delivery header
+     */
+    id: string;
+    /**
+     * - The parsed JSON payload
+     */
+    payload: any;
+    /**
+     * - The request protocol
+     */
+    protocol?: string | undefined;
+    /**
+     * - The request host header
+     */
+    host?: string | undefined;
+    /**
+     * - The request URL
+     */
+    url: string;
+    /**
+     * - The matched handler path
+     */
+    path: string;
+};
+/**
+ * @param {CreateHandlerOptions | CreateHandlerOptions[]} initOptions
+ * @returns {EventEmitter & {(req: import('node:http').IncomingMessage, res: import('node:http').ServerResponse, callback: (err?: Error) => void): void, sign(data: string | Buffer): string, verify(signature: string, data: string | Buffer): boolean}}
+ */
+declare function create(initOptions: CreateHandlerOptions | CreateHandlerOptions[]): EventEmitter & {
+    (req: import("node:http").IncomingMessage, res: import("node:http").ServerResponse, callback: (err?: Error) => void): void;
+    sign(data: string | Buffer): string;
+    verify(signature: string, data: string | Buffer): boolean;
+};
+import { EventEmitter } from 'node:events';
+//# sourceMappingURL=github-webhook-handler.d.ts.map
\ No newline at end of file
diff --git a/types/github-webhook-handler.d.ts.map b/types/github-webhook-handler.d.ts.map
new file mode 100644
index 0000000..9830adb
--- /dev/null
+++ b/types/github-webhook-handler.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"github-webhook-handler.d.ts","sourceRoot":"","sources":["../github-webhook-handler.js"],"names":[],"mappings":";;UAMc,MAAM;YACN,MAAM;;;;;;;WAMN,MAAM;;;;QACN,MAAM;;;;aACN,GAAG;;;;;;;;;;;;SAGH,MAAM;;;;UACN,MAAM;;AAwCpB;;;GAGG;AACH,qCAHW,oBAAoB,GAAG,oBAAoB,EAAE,GAC3C,YAAY,GAAG;IAAC,CAAC,GAAG,EAAE,OAAO,WAAW,EAAE,eAAe,EAAE,GAAG,EAAE,OAAO,WAAW,EAAE,cAAc,EAAE,QAAQ,EAAE,CAAC,GAAG,CAAC,EAAE,KAAK,KAAK,IAAI,GAAG,IAAI,CAAC;IAAC,IAAI,CAAC,IAAI,EAAE,MAAM,GAAG,MAAM,GAAG,MAAM,CAAC;IAAC,MAAM,CAAC,SAAS,EAAE,MAAM,EAAE,IAAI,EAAE,MAAM,GAAG,MAAM,GAAG,OAAO,CAAA;CAAC,CAyIvP;6BAtM4B,aAAa"}
\ No newline at end of file
diff --git a/types/tsconfig.tsbuildinfo b/types/tsconfig.tsbuildinfo
new file mode 100644
index 0000000..bfcb06f
--- /dev/null
+++ b/types/tsconfig.tsbuildinfo
@@ -0,0 +1 @@
+{"root":["../github-webhook-handler.js"],"version":"5.9.3"}
\ No newline at end of file