PeerJS: Simple peer-to-peer with WebRTC

PeerJS provides a complete, configurable, and easy-to-use peer-to-peer API built on top of WebRTC, supporting both data channels and media streams.

Live Example

Here's an example application that uses both media and data connections: https://glitch.com/~peerjs-video. The example also uses its own PeerServer.

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Setup

Include the library

with npm: npm install peerjs

with yarn: yarn add peerjs

// The usage -
import { Peer } from "peerjs";

Create a Peer

const peer = new Peer("pick-an-id");
// You can pick your own id or omit the id if you want to get a random one from the server.

Data connections

Connect

const conn = peer.connect("another-peers-id");
conn.on("open", () => {
    conn.send("hi!");
});

Receive

peer.on("connection", (conn) => {
    conn.on("data", (data) => {
        // Will print 'hi!'
        console.log(data);
    });
    conn.on("open", () => {
        conn.send("hello!");
    });
});

Media calls

Call

navigator.mediaDevices.getUserMedia(
    { video: true, audio: true },
    (stream) => {
        const call = peer.call("another-peers-id", stream);
        call.on("stream", (remoteStream) => {
            // Show stream in some <video> element.
        });
    },
    (err) => {
        console.error("Failed to get local stream", err);
    },
);

Answer

peer.on("call", (call) => {
    navigator.mediaDevices.getUserMedia(
        { video: true, audio: true },
        (stream) => {
            call.answer(stream); // Answer the call with an A/V stream.
            call.on("stream", (remoteStream) => {
                // Show stream in some <video> element.
            });
        },
        (err) => {
            console.error("Failed to get local stream", err);
        },
    );
});

Running tests

npm test

Browser support

Firefox	Chrome	Edge	Safari
80+	83+	83+	15+

We test PeerJS against these versions of Chrome, Edge, Firefox, and Safari with BrowserStack to ensure compatibility. It may work in other and older browsers, but we don't officially support them. Changes to browser support will be a breaking change going forward.

[!NOTE] Firefox 102+ is required for CBOR / MessagePack support.

FAQ

Q. I have a message Critical dependency: the request of a dependency is an expression in browser's console

A. The message occurs when you use PeerJS with Webpack. It is not critical! It relates to Parcel https://github.com/parcel-bundler/parcel/issues/2883 We'll resolve it when updated to Parcel V2.