JSON-RPC 2.0 server and client library, with HTTP, TCP and Websocket endpoints

Usage no npm install needed!

<script type="module">
  import jsonRpc2 from 'https://cdn.skypack.dev/json-rpc2';


Build Status



JSON-RPC 2.0 server and client library, with HTTP (with Websocket support) and TCP endpoints

This fork is a rewrite with proper testing framework, linted code, compatible with node 0.8.x and 0.10.x, class inheritance, and added functionalities


Check jsonrpc2-tools for some nice additions to this module.


To install node-jsonrpc2 in the current directory, run:

npm install json-rpc2 --save

Changes from 1.x

  • Uses native EventEmitter instead of EventEmitter3

Changes from 0.x

  • Before, the id member was permissive and wouldn't actually adhere to the RFC, allowing anything besides undefined.
  • If your application relied on weird id constructs other than String, Number or null, it might break if you update to 1.x


Firing up an efficient JSON-RPC server becomes extremely simple:

var rpc = require('json-rpc2');

var server = rpc.Server.$create({
    'websocket': true, // is true by default
    'headers': { // allow custom headers is empty by default
        'Access-Control-Allow-Origin': '*'

function add(args, opt, callback) {
  callback(null, args[0] + args[1]);

server.expose('add', add);

// you can expose an entire object as well:

server.expose('namespace', {
    'function1': function(){},
    'function2': function(){},
    'function3': function(){}
// expects calls to be namespace.function1, namespace.function2 and namespace.function3

// listen creates an HTTP server on localhost only
server.listen(8000, 'localhost');

And creating a client to speak to that server is easy too:

var rpc = require('json-rpc2');

var client = rpc.Client.$create(8000, 'localhost');

// Call add function on the server

client.call('add', [1, 2], function(err, result) {
    console.log('1 + 2 = ' + result);

Create a raw (socket) server using:

var rpc = require('json-rpc2');

var server = rpc.Server.$create();

// non-standard auth for RPC, when using this module using both client and server, works out-of-the-box
server.enableAuth('user', 'pass');

// Listen on socket
server.listenRaw(8080, 'localhost');

Extend, overwrite, overload

Any class can be extended, or used as a mixin for new classes, since it uses ES5Class module.

For example, you may extend the Endpoint class, that automatically extends Client and Server classes. Extending Connection automatically extends SocketConnection and HttpServerConnection.

var rpc = require('json-rpc2');

    'newFunction': function(){


    server = rpc.Server.$create(),
    client = rpc.Client.$create();

server.newFunction(); // already available
client.newFunction(); // already available

To implement a new class method (that can be called without an instance, like rpc.Endpoint.newFunction):

var rpc = require('json-rpc2');

    'newFunction': function(){

rpc.Endpoint.newFunction(); // available
rpc.Client.newFunction(); // every
rpc.Server.newFunction(); // where

Don't forget, when you are overloading an existing function, you can call the original function using $super

var rpc = require('json-rpc2');

    'trace': function($super, direction, message){
        $super(' (' + direction + ')', message); //call the last defined function

And you can start your classes directly from any of the classes

var MyCoolServer = require('json-rpc2').Server.$define('MyCoolServer', {
    myOwnFunction: function(){
}, {
    myOwnClassMethod: function(){
}); // MyCoolServer will contain all class and instance functions from Server

MyCoolServer.myOwnClassMethod(); // class function
MyCoolServer.$create().myOwnFunction(); // instance function


This module uses the debug package, to debug it, you need to set the Node environment variable to jsonrpc, by setting it in command line as set DEBUG=jsonrpc or export DEBUG=jsonrpc


To learn more, see the examples directory, peruse test/jsonrpc-test.js, or simply "Use The Source, Luke".

More documentation and development is on its way.