diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..f19deff
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,22 @@
+import { EventEmitter } from "events";
+import { BaseMQTTSNPacket, MQTTPacket } from "./packet";
+
+type OnPacketFn = <T extends MQTTPacket = MQTTPacket>(packet: T) => void;
+
+interface Parser extends EventEmitter {
+  parse(buf: Buffer): number;
+
+  on(event: "packet", listener: OnPacketFn): this;
+  off(event: "packet", listener: OnPacketFn): this;
+  once(event: "packet", listener: OnPacketFn): this;
+  addListener(event: "packet", listener: OnPacketFn): this;
+  prependListener(event: "packet", listener: OnPacketFn): this;
+  prependOnceListener(event: "packet", listener: OnPacketFn): this;
+  listeners(event: "packet"): Function[];
+  rawListeners(event: "packet"): Function[];
+}
+
+export var parser: {
+  new(opts?: { isClient?: boolean }): Parser;
+};
+export function generate<P extends BaseMQTTSNPacket = BaseMQTTSNPacket>(packet: P): Buffer;
diff --git a/package.json b/package.json
index 7aa6dc4..0e408f1 100644
--- a/package.json
+++ b/package.json
@@ -3,6 +3,7 @@
   "version": "0.0.2",
   "description": "Parse and generate MQTT-SN packets",
   "main": "mqttsn.js",
+  "typings": "./index.d.ts",
   "scripts": {
     "test": "tape test.js | faucet"
   },
diff --git a/packet.d.ts b/packet.d.ts
new file mode 100644
index 0000000..01b6075
--- /dev/null
+++ b/packet.d.ts
@@ -0,0 +1,193 @@
+type ReturnCodeString =
+  | "Accepted"
+  | "Rejected: congestion"
+  | "Rejected: invalid topic ID"
+  | "Rejected: not supported";
+
+type QOS = number;
+
+type TopicType =
+  | "normal"
+  | "pre-defined"
+  | "short topic";
+
+interface BaseMQTTSNPacket {
+  cmd: "advertise" | "searchgw" | "gwinfo" | "connect" | "connack" | "willtopicresp" | "willmsgresp" | "willtopicreq"
+    | "willmsgreq" | "pingresp" | "willtopic" | "willtopicupd" | "willmsg" | "willmsgupd" | "register" | "regack"
+    | "publish" | "puback" | "pubcomp" | "pubrec" | "pubrel" | "unsuback" | "unsubscribe" | "subscribe" | "suback"
+    | "pingreq" | "disconnect";
+
+  length?: number;
+}
+
+interface GenericAck extends BaseMQTTSNPacket {
+  returnCode: ReturnCodeString | null;
+}
+
+interface Advertise extends BaseMQTTSNPacket {
+  cmd: "advertise";
+  gwId: number;
+  duration: number;
+}
+
+interface SearchGw extends BaseMQTTSNPacket {
+  cmd: "searchgw";
+  radius: number;
+}
+
+interface GwInfo extends BaseMQTTSNPacket {
+  cmd: "gwinfo";
+  gwId: number;
+  gwAdd?: Buffer;
+}
+
+interface Connect extends BaseMQTTSNPacket {
+  cmd: "connect";
+  duration: number;
+  clientId: string;
+  will: boolean;
+  cleanSession: boolean;
+}
+
+interface ConnAck extends GenericAck {
+  cmd: "connack";
+}
+
+interface WillTopic extends BaseMQTTSNPacket {
+  cmd: "willtopic";
+  qos?: QOS;
+  retain?: boolean;
+  willTopic?: string;
+}
+
+interface WillTopicResp extends GenericAck {
+  cmd: "willtopicresp";
+}
+
+interface WillTopicUpd extends BaseMQTTSNPacket {
+  cmd: "willtopicupd";
+  qos?: QOS;
+  retain?: boolean;
+  willTopic?: string;
+}
+
+interface WillMsg extends BaseMQTTSNPacket {
+  cmd: "willmsg";
+  willMsg: string;
+}
+
+interface WillMsgResp extends GenericAck {
+  cmd: "willmsgresp";
+}
+
+interface WillMsgUpd extends WillMsg {
+  cmd: "willmsgupd";
+}
+
+interface Register extends BaseMQTTSNPacket {
+  cmd: "register";
+  topicId: number;
+  msgId: number;
+  topicName: string;
+}
+
+interface RegAck extends GenericAck {
+  cmd: "regack";
+  topicId: number;
+  msgId: number;
+}
+
+interface Publish<TT extends TopicType, TID> extends BaseMQTTSNPacket {
+  cmd: "publish";
+  dup: boolean;
+  qos: QOS;
+  topicIdType: TT;
+  topicId: TID;
+  msgId: number;
+  payload: Buffer;
+}
+
+type PublishShortTopic = Publish<TopicType.SHORT, string>;
+type PublishPredefined = Publish<TopicType.PREDEFINED, number>;
+type PublishRegisteredTopic = Publish<TopicType.NORMAL, number>;
+
+interface PubAck extends GenericAck {
+  cmd: "puback";
+  topicId: number;
+  msgId: number;
+}
+
+interface PubComp extends BaseMQTTSNPacket {
+  cmd: "pubcomp";
+  msgId: number;
+}
+
+interface PubRec extends BaseMQTTSNPacket {
+  cmd: "pubrec";
+  msgId: number;
+}
+
+interface PubRel extends BaseMQTTSNPacket {
+  cmd: "pubrel";
+  msgId: number;
+}
+
+interface UnsubAck extends BaseMQTTSNPacket {
+  cmd: "unsuback";
+  msgId: number;
+}
+
+interface Unsubscribe<TT extends TopicType, TN, TID> extends BaseMQTTSNPacket {
+  cmd: "unsubscribe";
+  msgId: number;
+  topicIdType: TT;
+  topicName: TN;
+  topicId: TID;
+}
+
+type UnsubscribePredefined = Unsubscribe<TopicType.PREDEFINED, undefined, number>;
+type UnsubscribeRegisteredTopic = Unsubscribe<TopicType.NORMAL, undefined, number>;
+type UnsubscribeShortTopic = Unsubscribe<TopicType.SHORT, string, undefined>;
+
+interface Subscribe<TT extends TopicType, TN, TID> extends Unsubscribe<TT, TN, TID> {
+  cmd: "subscribe";
+  dup: boolean;
+  qos: QOS;
+}
+
+declare type SubscribePredefined = Subscribe<TopicType.PREDEFINED, undefined, number>;
+declare type SubscribeRegisteredTopic = Subscribe<TopicType.NORMAL, undefined, number>;
+declare type SubscribeShortTopic = Subscribe<TopicType.SHORT, string, undefined>;
+
+interface SubAck extends GenericAck {
+  cmd: "suback";
+  topicId: number;
+  msgId: number;
+  qos: QOS;
+}
+
+interface PingReq extends BaseMQTTSNPacket {
+  cmd: "pingreq";
+  clientId?: string;
+}
+
+interface Disconnect extends BaseMQTTSNPacket {
+  cmd: "disconnect";
+  duration?: number;
+}
+
+
+export type MQTTPacket =
+  | Advertise | SearchGw | GwInfo
+  | Connect | Disconnect | ConnAck
+  | WillMsg | WillMsgUpd | WillTopic | WillTopicUpd | WillMsgResp | WillTopicResp
+  | Register
+  | RegAck
+  | PublishPredefined | PublishRegisteredTopic | PublishShortTopic
+  | PubAck | PubComp | PubRec | PubRel
+  | SubscribePredefined | SubscribeRegisteredTopic | SubscribeShortTopic
+  | SubAck
+  | UnsubscribePredefined | UnsubscribeRegisteredTopic | UnsubscribeShortTopic
+  | UnsubAck
+  | PingReq
+  | BaseMQTTSNPacket;
\ No newline at end of file