diff --git a/aedes.d.ts b/aedes.d.ts
index 0c0413a4..a520f9f3 100644
--- a/aedes.d.ts
+++ b/aedes.d.ts
@@ -80,6 +80,12 @@ declare namespace aedes {
 
   type PublishedHandler = (packet: AedesPublishPacket, client: Client, callback: (error?: Error | null) => void) => void
 
+  type LastHearthbeatTimestamp = Date;
+
+  interface Brokers {
+    [brokerId: string]: LastHearthbeatTimestamp;
+  }
+
   interface AedesOptions {
     mq?: any
     id?: string
@@ -101,6 +107,7 @@ declare namespace aedes {
     id: string
     connectedClients: number
     closed: boolean
+    brokers: Brokers
 
     handle: (stream: Connection) => Client
 
diff --git a/package.json b/package.json
index 8ee57e24..3436b2e7 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,8 @@
     "unit:report": "tap --no-esm -J test/*.js --cov --coverage-report=html --coverage-report=cobertura | tee out.tap",
     "typescript": "tsc --project ./test/types/tsconfig.json",
     "test:report": "npm run lint && npm run unit:report && npm run typescript",
-    "test": "npm run lint && npm run unit && npm run typescript",
+    "test": "npm run lint && npm run unit && npm run typescript && tsd",
+    "test:types": "tsd",
     "test:ci": "npm run lint && npm run unit -- --cov --coverage-report=lcovonly && npm run typescript",
     "license-checker": "license-checker --production --onlyAllow=\"MIT;ISC;BSD-3-Clause;BSD-2-Clause\"",
     "release": "read -p 'GITHUB_TOKEN: ' GITHUB_TOKEN && export GITHUB_TOKEN=$GITHUB_TOKEN && release-it --disable-metrics"
@@ -38,6 +39,9 @@
   "pre-commit": [
     "test"
   ],
+  "tsd": {
+		"directory": "test/types"
+	},
   "repository": {
     "type": "git",
     "url": "https://github.com/moscajs/aedes.git"
@@ -103,6 +107,7 @@
     "snazzy": "^9.0.0",
     "standard": "^16.0.3",
     "tap": "^14.11.0",
+    "tsd": "^0.14.0",
     "typescript": "^4.1.2",
     "websocket-stream": "^5.5.2"
   },
diff --git a/test/types/aedes.test-d.ts b/test/types/aedes.test-d.ts
new file mode 100644
index 00000000..fd9d599c
--- /dev/null
+++ b/test/types/aedes.test-d.ts
@@ -0,0 +1,163 @@
+/* eslint no-unused-vars: 0 */
+/* eslint no-undef: 0 */
+
+import { expectType } from 'tsd'
+import type {
+  Aedes,
+  Brokers,
+  Client,
+  Connection,
+  ConnackPacket,
+  AuthenticateError,
+  AedesPublishPacket,
+  PublishPacket,
+  Subscription,
+  SubscribePacket,
+  UnsubscribePacket
+} from '../../aedes'
+import { Server } from '../../aedes'
+import type { Packet } from 'mqtt-packet'
+import { Socket } from 'net'
+
+// Aedes server
+const broker = Server({
+  concurrency: 100,
+  heartbeatInterval: 60000,
+  connectTimeout: 30000,
+  id: 'aedes',
+  preConnect: (client: Client, packet: Packet, callback) => {
+    if (client.req) {
+      callback(new Error('not websocket stream'), false)
+    }
+    if (client.conn instanceof Socket && client.conn.remoteAddress === '::1') {
+      callback(null, true)
+    } else {
+      callback(new Error('connection error'), false)
+    }
+  },
+  authenticate: (client: Client, username: string, password: Buffer, callback) => {
+    if (username === 'test' && password === Buffer.from('test') && client.version === 4) {
+      callback(null, true)
+    } else {
+      const error = new Error() as AuthenticateError
+      error.returnCode = 1
+
+      callback(error, false)
+    }
+  },
+  authorizePublish: (client: Client, packet: PublishPacket, callback) => {
+    if (packet.topic === 'aaaa') {
+      return callback(new Error('wrong topic'))
+    }
+
+    if (packet.topic === 'bbb') {
+      packet.payload = Buffer.from('overwrite packet payload')
+    }
+
+    callback(null)
+  },
+  authorizeSubscribe: (client: Client, sub: Subscription, callback) => {
+    if (sub.topic === 'aaaa') {
+      return callback(new Error('wrong topic'))
+    }
+
+    if (sub.topic === 'bbb') {
+      // overwrites subscription
+      sub.qos = 2
+    }
+
+    callback(null, sub)
+  },
+  authorizeForward: (client: Client, packet: AedesPublishPacket) => {
+    if (packet.topic === 'aaaa' && client.id === 'I should not see this') {
+      return null
+      // also works with return undefined
+    } else if (packet.topic === 'aaaa' && client.id === 'I should not see this either') {
+      return
+    }
+
+    if (packet.topic === 'bbb') {
+      packet.payload = Buffer.from('overwrite packet payload')
+    }
+
+    return packet
+  }
+})
+
+expectType<Aedes>(broker)
+
+expectType<Brokers>(broker.brokers)
+
+expectType<Aedes>(broker.on('closed', () => {}))
+expectType<Aedes>(broker.on('client', (client: Client) => {}))
+expectType<Aedes>(broker.on('clientError', (client: Client, error: Error) => {}))
+expectType<Aedes>(broker.on('connackSent', (packet: ConnackPacket, client: Client) => {}))
+
+expectType<void>(broker.publish(
+  {} as PublishPacket,
+  (error?: Error) => {
+    if (error) {
+      console.error(error)
+    }
+  }
+))
+
+expectType<void>(broker.subscribe(
+  'topic',
+  (packet: AedesPublishPacket, callback: () => void) => {},
+  () => {}
+))
+
+expectType<void>(broker.unsubscribe(
+  'topic',
+  (packet: AedesPublishPacket, callback: () => void) => {},
+  () => {}
+))
+
+expectType<void>(broker.close())
+expectType<void>(broker.close(() => {}))
+
+// Aedes client
+const client = broker.handle({} as Connection)
+
+expectType<Client>(client)
+
+expectType<Connection>(client.conn)
+
+expectType<Client>(client.on('connected', () => {}))
+expectType<Client>(client.on('error', (error: Error) => {
+  if (error) {
+    console.error(error)
+  }
+}))
+
+expectType<void>(client.publish({} as PublishPacket, (error?: Error) => {
+  if (error) {
+    console.error(error)
+  }
+}))
+expectType<void>(client.publish({} as PublishPacket))
+
+expectType<void>(client.subscribe({} as Subscription, (error?: Error) => {
+  if (error) {
+    console.error(error)
+  }
+}))
+expectType<void>(client.subscribe({} as Subscription))
+expectType<void>(client.subscribe([] as Subscription[]))
+expectType<void>(client.subscribe({} as SubscribePacket))
+
+expectType<void>(client.unsubscribe({} as Subscription, (error?: Error) => {
+  if (error) {
+    console.error(error)
+  }
+}))
+expectType<void>(client.unsubscribe({} as Subscription))
+expectType<void>(client.unsubscribe([] as Subscription[]))
+expectType<void>(client.unsubscribe({} as UnsubscribePacket))
+
+expectType<void>(client.emptyOutgoingQueue())
+expectType<void>(client.emptyOutgoingQueue(() => {}))
+
+expectType<void>(client.close())
+expectType<void>(client.close(() => {}))
diff --git a/test/types/index.ts b/test/types/index.ts
index b0dd7e40..fccff60c 100644
--- a/test/types/index.ts
+++ b/test/types/index.ts
@@ -69,6 +69,8 @@ const broker = Server({
   }
 })
 
+const { brokers } = broker
+
 const server = createServer(broker.handle)
 
 broker.on('closed', () => {