diff --git a/CHANGELOG.md b/CHANGELOG.md
index bf514a6..5e43e5a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+## 3.0.0-beta.0
+
+**New Feature:**
+
+* [#55](https://github.com/rikulo/socket.io-client-dart/issues/55) how to custom parser
+
+
 ## 2.0.3+1
 
 Fix dart analyzing issues
diff --git a/lib/src/darty.dart b/lib/src/darty.dart
index a111598..987754b 100644
--- a/lib/src/darty.dart
+++ b/lib/src/darty.dart
@@ -3,6 +3,7 @@
 // Author: jumperchen<jumperchen@potix.com>
 
 import 'package:socket_io_client/socket_io_client.dart';
+import 'package:socket_io_common/socket_io_common.dart';
 import 'package:socket_io_common/src/util/event_emitter.dart';
 
 /// Default event listeners for dart way API.
@@ -60,6 +61,13 @@ extension DartySocket on Socket {
   }
 }
 
+/// Parser options
+class ParserOptions {
+  final Encoder Function() encoder;
+  final Decoder Function() decoder;
+  ParserOptions({required this.encoder, required this.decoder});
+}
+
 /// Option Builder to help developer to construct an options map.
 class OptionBuilder {
   final Map<String, dynamic> _opts;
@@ -114,6 +122,11 @@ class OptionBuilder {
     return this;
   }
 
+  /// The parser used to marshall/unmarshall packets for transport.
+  OptionBuilder setParser(ParserOptions parserOptions) {
+    _opts['parser'] = parserOptions;
+    return this;
+  }
   OptionBuilder setReconnectionAttempts(num attempts) {
     _opts['reconnectionAttempts'] = attempts;
     return this;
diff --git a/lib/src/manager.dart b/lib/src/manager.dart
index 65d1abd..c77207d 100644
--- a/lib/src/manager.dart
+++ b/lib/src/manager.dart
@@ -96,8 +96,8 @@ class Manager extends EventEmitter {
     this.uri = uri;
 
     if (options['parser'] != null) {
-      encoder = options['parser'].Encoder();
-      decoder = options['parser'].Decoder();
+      encoder = options['parser'].encoder();
+      decoder = options['parser'].decoder();
     } else {
       encoder = Encoder();
       decoder = Decoder();
diff --git a/pubspec.yaml b/pubspec.yaml
index 9ee2f76..a614502 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -17,8 +17,8 @@ dependencies:
 dev_dependencies:
   lints: ^3.0.0
   test: ">=1.3.0 <2.0.0"
-#  build_runner: any
-#  build_web_compilers: any
+  build_runner: any
+  build_web_compilers: any
 #  socket_io: any // support Socket.io v2.* only
 
   
diff --git a/test_nodejs/server.js b/test_nodejs/server.js
index 74be9d7..e1c131b 100644
--- a/test_nodejs/server.js
+++ b/test_nodejs/server.js
@@ -13,7 +13,11 @@
 'use strict';
 const app = require('express')();
 const server = require('http').createServer(app);
-const io = require('socket.io')(server);
+const io = require('socket.io')(server, {
+    cors: {
+        origin: '*',
+    }
+});
 io.on('connection', userSocket => {
     console.log('connected');
     userSocket.on('toServer', data => {
diff --git a/web/main.dart b/web/main.dart
index 1455c30..63f65cb 100644
--- a/web/main.dart
+++ b/web/main.dart
@@ -12,18 +12,42 @@ import 'dart:async';
  * Copyright (C) 2017 Potix Corporation. All Rights Reserved.
  */
 import 'package:socket_io_client/socket_io_client.dart' as io;
+import 'package:socket_io_common/socket_io_common.dart';
 
 void main() {
-  var socket = io.io('http://localhost:3000');
-  socket.on('connect', (_) {
-    print('connect');
-    socket.emit('msg', 'init');
+  var socket = io.io(
+      'http://localhost:3000',
+      io.OptionBuilder().setTransports(['polling'])
+      .setParser(io.ParserOptions(encoder: () => MyEncoder(), decoder: () => MyDecoder()))
+      // .disableAutoConnect()
+          .build());
+
+  // socket.connect();
+
+  socket.onConnect((_) {
+    socket.emit('toServer', 'init');
+
     var count = 0;
     Timer.periodic(const Duration(seconds: 1), (Timer countDownTimer) {
-      socket.emit('msg', count++);
+      socket.emit('toServer', count++);
     });
   });
+
   socket.on('event', (data) => print(data));
   socket.on('disconnect', (_) => print('disconnect'));
   socket.on('fromServer', (_) => print(_));
 }
+class MyEncoder extends Encoder {
+  @override
+  List<Object?> encode(Object? obj) {
+    print('MyEncoder: $obj');
+    return super.encode(obj);
+  }
+}
+class MyDecoder extends Decoder {
+  @override
+  add(obj) {
+    print('MyDecoder: $obj');
+    return super.add(obj);
+  }
+}
\ No newline at end of file