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JSON-RPC 2.0 implementation over WebSockets for Node.js and JavaScript/TypeScript


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WebSockets for Node.js and JavaScript/TypeScript with JSON RPC 2.0 support on top.


The rpc-websockets library enables developers to easily implement their business logic that includes messaging between users, machines or any devices. It provides a possibility to send and receive JSON data through the WebSocket communication protocol in order to support two-way notification push, running RPC methods and firing any types of event signalling. Only clients can call RPC methods and not vice versa at the moment. Both frontend (HTML/JS-based) and backend (Node.js-based) development environments are supported.

rpc-websockets is built on Node.js and supports both LTS and Current versions.

Use the free OSS edition in order to implement and manage your own WebSocket server instances, or subscribe for our Pro plan and have us manage your instances and provide you with management of your methods, events and notifications on an easy-to-use Web Management portal.

Quick start

Install our OSS library in your project:

npm install rpc-websockets

Write your source code using rpc-websockets:

var WebSocket = require('rpc-websockets').Client
var WebSocketServer = require('rpc-websockets').Server

// instantiate Server and start listening for requests
var server = new WebSocketServer({
  port: 8080,
  host: 'localhost'

// register an RPC method
server.register('sum', function(params) {
  return params[0] + params[1]

// ...and maybe a protected one also
server.register('account', function() {
  return ['confi1', 'confi2']

// create an event

// get events

// emit an event to subscribers

// close the server

// instantiate Client and connect to an RPC server
var ws = new WebSocket('ws://localhost:8080')

ws.on('open', function() {
  // call an RPC method with parameters'sum', [5, 3]).then(function(result) {
    require('assert').equal(result, 8)

  // send a notification to an RPC server

  // subscribe to receive an event

  ws.on('feedUpdated', function() {

  // unsubscribe from an event

  // login your client to be able to use protected methods
  ws.login({'username': 'confi1', 'password':'foobar'}).then(function() {'account').then(function(result) {
      require('assert').equal(result, ['confi1', 'confi2'])
  }).catch(function(error) {
    console.log('auth failed')

  // close a websocket connection


Please consult our API documentation for both WebSocket server and client JavaScript and TypeScript classes.

OSS Features

Features of the free open-source edition.

OSS Features

All library's open-source features are documented in our API documentation and can be used free of charge. You are free to implement your solutions based on provided methods in any way you are comfortable with, as long as you use our work along our very permissive license conditions.

Pro Features

In order to support your production-ready environments, we can provide you with additional features built on top of our free OSS edition along with the skill set to turn your business case or a Proof-of-Concept idea into reality.

Pro Features

Describe us your use case by contacting us and we will swiftly get back to you with a proposed solution that meets your needs.

Professional support

We offer professional support for rpc-websockets and beyond. We have many years of expertise on building robust, scalable Node.js applications and can help you overcome issues and challenges preventing you to ship your great products. We excel in software architecture and implementation, being able to provide you with development, planning, consulting, training and customization services. Feel free to contact us so we can discuss how to help you finish your products!


rpc-websockets is being actively used in production by multiple companies in a variety of different use cases.

ScratchboxLoom NetworkuniqCastLeapDAOKlika Tech, Inc.Kodebox, Inc.Hey-Group S.A./N.V.Hylo, Inc.Witnet FoundationScale LeapCodice Foundation, Inc.Holo Ltd.Solana Labs, Inc.Filecoin


Become a sponsor and get your logo on project's README on GitHub with a link to your site. Feel free to contact us for the arrangement!


This library is licensed under LGPLv3. Please see LICENSE for licensing details.