diff --git a/__tests__/event_manager.test.ts b/__tests__/event_manager.test.ts
index e85256b..20f95d3 100644
--- a/__tests__/event_manager.test.ts
+++ b/__tests__/event_manager.test.ts
@@ -12,6 +12,7 @@ jest.setTimeout(180000);
 
 describe('Event Handler', function() {
   const ain = new Ain(test_node_3, test_event_handler_node);
+  const customClientId = 'myCustomClientId';
   let eventFilterId: string;
   let connectionCount = 0;
   let disconnectionCount = 0;
@@ -28,7 +29,7 @@ describe('Event Handler', function() {
     expect(connectionCount).toBe(0);
     expect(disconnectionCount).toBe(0);
 
-    await ain.em.connect(connectionCb, disconnectionCb);
+    await ain.em.connect(connectionCb, disconnectionCb, customClientId);
 
     expect(connectionCount).toBe(1);
     expect(disconnectionCount).toBe(0);
@@ -59,6 +60,12 @@ describe('Event Handler', function() {
     });
   });
 
+  describe('Custom client id setting', () => {
+    it('getCustomClientId()', async () => {
+      expect(ain.em.getCustomClientId()).toBe(customClientId);
+    });
+  });
+
   describe('BLOCK_FINALIZED', () => {
     it('Subscribe to BLOCK_FINALIZED', (done) => {
       eventFilterId = ain.em.subscribe('BLOCK_FINALIZED', {
diff --git a/package.json b/package.json
index e692962..b09ab46 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ainblockchain/ain-js",
-  "version": "1.12.0",
+  "version": "1.13.0",
   "description": "",
   "main": "lib/ain.js",
   "scripts": {
diff --git a/src/event-manager/event-channel-client.ts b/src/event-manager/event-channel-client.ts
index c6534af..38f87ae 100644
--- a/src/event-manager/event-channel-client.ts
+++ b/src/event-manager/event-channel-client.ts
@@ -27,6 +27,8 @@ export default class EventChannelClient {
   private _ws?: WebSocket | WebSocketBE;
   /** Whether it's connected or not. */
   private _isConnected: boolean;
+  /** The custom client id of the event channel. */
+  private _customClientId: string;
   /** The handshake timeout object. */
   private _handshakeTimeout?: ReturnType<typeof setTimeout> | null;
   /** The heartbeat timeout object. */
@@ -42,6 +44,7 @@ export default class EventChannelClient {
     this._eventCallbackManager = eventCallbackManager;
     this._ws = undefined;
     this._isConnected = false;
+    this._customClientId = '';
     this._handshakeTimeout = undefined;
     this._heartbeatTimeout = undefined;
   }
@@ -54,9 +57,10 @@ export default class EventChannelClient {
    * Opens a new event channel.
    * @param {ConnectionCallback} connectionCallback The connection callback function.
    * @param {DisconnectionCallback} disconnectionCallback The disconnection callback function.
+   * @param {string} customClientId The custom client id to set.
    * @returns {Promise<void>} A promise for the connection success.
    */
-  connect(connectionCallback?: ConnectionCallback, disconnectionCallback?: DisconnectionCallback): Promise<any> {
+  connect(connectionCallback?: ConnectionCallback, disconnectionCallback?: DisconnectionCallback, customClientId?: string): Promise<any> {
     return new Promise(async (resolve, reject) => {
       if (this.isConnected) {
         reject(new Error(`Can't connect multiple channels`));
@@ -139,6 +143,10 @@ export default class EventChannelClient {
         }
         // Heartbeat timeout
         this.startHeartbeatTimer(DEFAULT_HEARTBEAT_INTERVAL_MS);
+        // Custom client id
+        if (customClientId) {
+          this.setCustomClientId(customClientId);
+        }
         // Connection callback
         if (connectionCallback) {
           connectionCallback(this._ws);
@@ -291,30 +299,48 @@ export default class EventChannelClient {
   }
 
   /**
-   * Sends a register-event-filter messsage to the event channel.
+   * Sends a SET_CUSTOM_CLIENT_ID messsage to the event channel.
+   * @param {string} customClientId The custom client id to set.
+   */
+  setCustomClientId(customClientId: string) {
+    this._customClientId = customClientId;
+    const data = { customClientId };
+    const message = this.buildMessage(EventChannelMessageTypes.SET_CUSTOM_CLIENT_ID, data);
+    this.sendMessage(message);
+  }
+
+  /**
+   * Returns the custom client id saved on the client side.
+   */
+  getCustomClientId() {
+    return this._customClientId;
+  }
+
+  /**
+   * Sends a REGISTER_FILTER messsage to the event channel.
    * @param {EventFilter} filter The event filter to register.
    */
   registerFilter(filter: EventFilter) {
-    const filterObj = filter.toObject();
-    const registerMessage = this.buildMessage(EventChannelMessageTypes.REGISTER_FILTER, filterObj);
-    this.sendMessage(registerMessage);
+    const data = filter.toObject();
+    const message = this.buildMessage(EventChannelMessageTypes.REGISTER_FILTER, data);
+    this.sendMessage(message);
   }
 
   /**
-   * Sends a deregister-event-filter messsage to the event channel.
+   * Sends a DEREGISTER_FILTER messsage to the event channel.
    * @param {EventFilter} filter The event filter to deregister.
    */
   deregisterFilter(filter: EventFilter) {
-    const filterObj = filter.toObject();
-    const deregisterMessage = this.buildMessage(EventChannelMessageTypes.DEREGISTER_FILTER, filterObj);
-    this.sendMessage(deregisterMessage);
+    const data = filter.toObject();
+    const message = this.buildMessage(EventChannelMessageTypes.DEREGISTER_FILTER, data);
+    this.sendMessage(message);
   }
 
   /**
-   * Sends a pong message.
+   * Sends a PONG message.
    */
   sendPong() {
-    const pongMessage = this.buildMessage(EventChannelMessageTypes.PONG, {});
-    this.sendMessage(pongMessage);
+    const message = this.buildMessage(EventChannelMessageTypes.PONG, {});
+    this.sendMessage(message);
   }
 }
diff --git a/src/event-manager/index.ts b/src/event-manager/index.ts
index 4ca1363..3d85b8e 100644
--- a/src/event-manager/index.ts
+++ b/src/event-manager/index.ts
@@ -47,9 +47,10 @@ export default class EventManager {
    * Opens a new event channel.
    * @param {ConnectionCallback} ConnectionCallback The connection callback function.
    * @param {DisconnectionCallback} disconnectionCallback The disconnection callback function.
+   * @param {string} customClientId The custom client id to set.
    */
-  async connect(connectionCallback?: ConnectionCallback, disconnectionCallback?: DisconnectionCallback) {
-    await this._eventChannelClient.connect(connectionCallback, disconnectionCallback);
+  async connect(connectionCallback?: ConnectionCallback, disconnectionCallback?: DisconnectionCallback, customClientId?: string) {
+    await this._eventChannelClient.connect(connectionCallback, disconnectionCallback, customClientId);
   }
 
   /**
@@ -59,6 +60,13 @@ export default class EventManager {
     this._eventChannelClient.disconnect();
   }
 
+  /**
+   * Returns the custom client id of the event channel saved on the client side.
+   */
+  getCustomClientId() {
+    return this._eventChannelClient.getCustomClientId();
+  }
+
   subscribe(
     eventType: 'BLOCK_FINALIZED',
     config: BlockFinalizedEventConfig,
diff --git a/src/types.ts b/src/types.ts
index 8a3e7e5..4ccefc3 100755
--- a/src/types.ts
+++ b/src/types.ts
@@ -346,6 +346,7 @@ export enum BlockchainEventTypes {
  * Event channel message types for blockchain event handler.
  */
 export enum EventChannelMessageTypes {
+  SET_CUSTOM_CLIENT_ID = 'SET_CUSTOM_CLIENT_ID',
   REGISTER_FILTER = 'REGISTER_FILTER',
   DEREGISTER_FILTER = 'DEREGISTER_FILTER',
   EMIT_EVENT = 'EMIT_EVENT',
@@ -497,9 +498,9 @@ export type FilterDeletedEventCallback = (event: FilterDeletedEvent) => void;
 /**
  * A type for connection callback functions (blockchain event handler).
  */
-export type ConnectionCallback = (webSocket) => void;
+export type ConnectionCallback = (webSocket: any) => void;
 
 /**
  * A type for disconnection callback functions (blockchain event handler).
  */
-export type DisconnectionCallback = (webSocket) => void;
+export type DisconnectionCallback = (webSocket: any) => void;