Sinch RTC SDK for JavaScript

The Sinch RTC SDK enables real-time voice and video calling directly in web applications. It provides a complete client-side solution for building in-app calling experiences in the browser.

Features

• App-to-App Calling — High-quality voice and video calls between users in your application
• App-to-PSTN Calling — Call regular phone numbers directly from the browser
• App-to-SIP Calling — Connect to SIP endpoints for enterprise telephony integration
• App-to-Conference Calling — Join multi-party conference calls from the browser

Prerequisites

1. Register a Sinch account
2. Create an application in the Dashboard to obtain an Application Key and Application Secret

Installation

npm install sinch-rtc

Quick Start

import { Sinch } from "sinch-rtc";

const sinchClient = Sinch.getSinchClientBuilder()
  .applicationKey("YOUR_APP_KEY")
  .userId("YOUR_USER_ID")
  .build();

sinchClient.addListener({
  onClientStarted: (client) => {
    console.log("Sinch client started");
  },
  onClientFailed: (client, error) => {
    console.error("Sinch client failed", error);
  },
  onCredentialsRequired: (client, registrationCallback) => {
    // Fetch a signed JWT from your backend and pass it to the callback.
    // Never embed the Application Secret in client-side code.
    fetch("/api/sinch-jwt?userId=YOUR_USER_ID")
      .then((res) => res.json())
      .then(({ jwt }) => registrationCallback.register(jwt));
  },
});

sinchClient.start();

Please find more about how to generate JWT in our documentation.

Making a Call

const callClient = sinchClient.getCallClient();

callClient.addListener({
  onIncomingCall: (client, call) => {
    call.answer();
  },
});

const call = callClient.callUser("REMOTE_USER_ID");

call.addListener({
  onCallProgressing: (call) => {
    console.log("Ringing...");
  },
  onCallEstablished: (call) => {
    console.log("Call established");
  },
  onCallEnded: (call) => {
    console.log("Call ended");
  },
});

Key Components

| Component | Description | | --------------- | ------------------------------------------------------------------------------------------------------ | | SinchClient | Primary entry point — manages configuration, authentication, and feature controllers | | CallClient | Exposes APIs to place and receive calls, notifies about incoming call events | | Call | Represents an active call with methods for answering, declining, and hanging up | | Listeners | SinchClientListener, CallClientListener, and CallListener provide callbacks for state and events |

Documentation

• Getting Started Guide
• Full API Reference
• JavaScript Reference App
• Try the Live Sample

License

ISC