Cordova WebSocket Plugin for Android

Usage no npm install needed!

<script type="module">
  import cordovaPluginWebsocket from '';


cordova-plugin-websocket GitHub version

This is a Cordova plugin, which is being developed based on Jetty 8, makes WebSocket (RFC6455) available on Android.


  • Android 2.3 or later (recommended 4.1 or later)
  • cordova-android@3.6.0 or later, or compatible framework
  • cordova-plugin-whitelist or cordova-plugin-legacy-whitelist if using cordova-android@4.0.0 and later

The plugin for Cordova 2.x can be found here. However it is no longer maintained.

Supported Features

version WS protocol WSS protocol text message binary message
2.3.x (API 10)
4.0.x (API 14)
4.0.x (API 15)
4.1.x (API 16)
4.2.x (API 17)
4.3.x (API 18)
4.4.x and later - - - -


  • Since Android 4.4.x (KitKat) and later support WebSocket, this plugin is NOT used on there by default.
  • WSS protocol is only supported TLS. SSL is not supported.
  • Android 3.x (Honeycomb) are not supported (might work but is not tested).
  • In cordova-android@4.0.0 and later, this plugin can be used together with Crosswalk. In this case also it is not used on there by default since that supports WebSocket.
  • In order to support Android 5.x (Lollipop) and later, would be better to build with cordova-android@3.7.1 or later.


Use Cordova Command-Line Interface (CLI). At first check your CLI version:

$ cordova --version

If using 5.0.0 and later, you can install it via npm:

$ cordova plugin add cordova-plugin-websocket

If using other old versions, you can install it via GitHub:

$ cordova plugin add

Setting a Content-Security-Policy (CSP)

cordova-android@4.0.0 and later support SCP. In order to permit WebSocket access using cordova-plugin-whitelist, append connect-src directive in index.html:

connect-src ws:// wss://

For example:

  <meta http-equiv="Content-Security-Policy" content="default-src 'self' data: gap: 'unsafe-eval'; style-src 'self' 'unsafe-inline'; media-src *; connect-src ws:// wss://">

Upgrading from previous versions

Remove and then reinstall:

$ cordova plugin rm cordova-plugin-websocket
$ cordova plugin add cordova-plugin-websocket


  • When install this plugin, it adds INTERNET permission to platforms/android/AndroidManifest.xml. If remove this plugin, the permission is also removed at the same time even if it is required for other plugins.
  • It has not supported cordova-android@3.5.x and earlier since v0.12.0. Please make sure Android platform version is more than that:
$ cordova platform
Installed platforms: android 4.1.1


WebSocket(url[, protocols])

The WebSocket(url, protocols) constructor takes one or two arguments. The first argument, url, specifies the URL to which to connect. The second, protocols, is either a string or an array of strings.
A simple code is as follows:

document.addEventListener('deviceready', function () {
    var ws = new WebSocket('ws://');

    ws.onopen = function () {
        this.send('hello');         // transmit "hello" after connecting

    ws.onmessage = function (event) {
        console.log(;    // will be "hello"

    ws.onerror = function () {
        console.log('error occurred!');

    ws.onclose = function (event) {
        console.log('close code=' + event.code);
}, false);


This plugin has the following options. All these parameters are optional. Of course these don't affect built-in WebSocket.

key type default value supported version
origin string file:// (usually) >=v0.3.0
maxConnectTime number 75000 >=v0.4.0
maxTextMessageSize number -1 >=v0.4.0 (except v0.8.x)
maxBinaryMessageSize number -1 >=v0.4.0 (except v0.8.x)
override boolean false >=v0.8.0
agent string (depends on device) >=v0.9.0
perMessageDeflate boolean true >=v0.10.0

origin is a value to set a request header field. Default value is usually file://. This is the same value as when using built-in WebSocket.

maxConnectTime is time to wait for connection. A unit is millisecond.

maxTextMessageSize and maxBinaryMessageSize are receivable maximum size from a server. Default value is -1 (unlimited. depends on heap size of devices). A unit is byte.

override is a flag to force WebView to use this plugin even if it supports WebSocket. However in most cases it will be slower than built-in WebSocket.

agent is user-agent to set a request header field. Default value depends on devices. This is the same value as when using built-in WebSocket.

perMessageDeflate is a flag whether to use permessage-deflate extension. Default value is true. Sends data with compression if a server also supports permessage-deflate. However if mainly sending compressed binary like JPEG images, recommended to set to false.

If change these parameters, need to do before creating a instance:

WebSocket.pluginOptions = {
    origin: '',
    maxConnectTime: 5000,
    override: true

var ws = new WebSocket('ws://');


Transmits data to the server over the WebSocket connection. The data takes a string, a blob, or an arraybuffer.


An upper limit of the message size depends on heap size of devices. It would be better to consider a way to split the message if it is quite large.

close([code[, reason]])

Closes the WebSocket connection or connection attempt, if any.

For debug

This plugin has been available logging for debug since v0.12.0. The logging level can be adjusted with config.xml that is in your project directory:

<platform name="android">
    <preference name="LogLevel" value="DEBUG" />

If don't specify this parameter, default level is DEBUG. So at first you may be surprised to see many debug logs on logcat. To stop logs except errors, change the level to ERROR.

Change Log



This plugin is available under the terms of the Apache License Version 2.0.