NGSIP.js

A lightweight SIP/WebRTC client library for browsers. Connects over WebSocket (RFC 7118), handles SIP registration and INVITE dialogs, and delegates media to the browser's native RTCPeerConnection.

Features

• SIP REGISTER with digest authentication (RFC 2617)
• Outbound and inbound audio calls via INVITE/ACK/BYE
• WebSocket transport with keep-alive and auto-reconnect
• Multi-server connection pool — redundancy (all active) or single (failover) modes
• TypeScript-first, zero runtime dependencies

Quick Start

Install

npm install ngsip.js

Or load the UMD bundle directly:

<script src="dist/ngsip.umd.js"></script>

Connect and Register

import { UA } from 'ngsip.js';

const ua = new UA({
  uri: 'sip:[email protected]',
  password: 'secret',
  wsServers: [
    { uri: 'wss://sip.example.com:8443', priority: 1 },
    { uri: 'wss://sip-backup.example.com:8443', priority: 2 },
  ],
  connectionMode: 'redundancy',
});

ua.on('registered', server => console.log('Registered via', server.uri));
ua.on('primaryChanged', server => console.log('Primary is now', server?.uri));

ua.start();

Make a Call

const session = ua.call('sip:[email protected]');

session.on('confirmed', () => {
  // Attach remote audio
  const audio = document.createElement('audio');
  audio.autoplay = true;
  audio.srcObject = session.remoteAudioStream;
  document.body.appendChild(audio);
});

session.on('terminated', cause => console.log('Call ended:', cause));

Answer an Incoming Call

ua.on('newRTCSession', (session, request) => {
  console.log('Incoming call from', request.headers.from.uri.user);

  session.ring();   // sends 180 Ringing

  // Accept:
  session.answer();

  // Or reject:
  // session.terminate();
});

Hang Up

session.terminate();

Disconnect

ua.stop();

Configuration

See docs/api.md for full UAConfig reference.

Multi-Server / Redundancy

const ua = new UA({
  uri: 'sip:[email protected]',
  password: 'secret',
  wsServers: [
    { uri: 'wss://server1.example.com:8443', priority: 1 },
    { uri: 'wss://server2.example.com:8443', priority: 2 },
    { uri: 'wss://server3.example.com:8443', priority: 3 },
  ],
  connectionMode: 'redundancy', // all servers connected simultaneously
});

In redundancy mode all servers are connected and registered at the same time. The lowest-priority-number server with a live registration is used as the primary for outbound calls. If it drops, the next registered server takes over instantly.

In single mode only the highest-priority server is active. When it drops, a 5-second failover timer fires before the next server is activated.

RFC Coverage

See docs/rfc-compliance.md.

API Reference

See docs/api.md.