PeerJS
A JavaScript library that lets browsers connect directly to each other for data and video/audio calls.
- Stars
- 13.5k
- Forks
- 1.5k
- Licence
- MIT
- Language
- TypeScript
- Last update
- 8 months ago
- Type
- Library
What it is
PeerJS is a JavaScript library that wraps WebRTC, the browser technology for direct connections between users, in a simpler API. It lets web apps send data or start audio and video calls between peers identified by IDs. The README says it needs a PeerServer to help peers find each other, which is a separate project.
- Send text messages between two browser tabs using a peer ID
- Start a video call from one browser and answer it in another
- Build a small peer-to-peer data channel feature in a web app
Great for
- Web developers adding real-time chat or file-style data exchange between browsers
- Developers building simple video or audio call features in a web app
- Teams who want a TypeScript-based WebRTC wrapper with a small API
- Prototypes that connect two browsers without building their own signaling layer
Not ideal for
- People who need a finished app with no coding, since this is a library for developers
- Projects needing guaranteed connections across all networks, because the README does not describe NAT traversal or relay fallback
- Users needing support for very old browsers, since the README says only listed versions are officially supported
How to get it
- 1
Install with a package manager
You'll need: Node.js or a bundler such as Parcel or Webpack (README does not specify versions)
Install with npm
npm install peerjsInstall with yarn
yarn add peerjs - 2
Run it
- Install the package with npm or yarn
- Import Peer from "peerjs"
- Create a peer with new Peer("pick-an-id") or omit the id to get a random one
- Connect to another peer ID with peer.connect() and send data once the connection opens
- 3
Get the most out of it
- Use the official API docs at peerjs.com/docs for full options
- Run a PeerServer (peers/peerjs-server) if you need your own signaling server, as the live example does
- Check the changelog when upgrading, since the README says browser support changes will be breaking
- Use Firefox 102+ if you need CBOR or MessagePack serialization
Downloads
Strengths
- Small, focused API: create a peer, connect, send data, or call
- Tested against current Chrome, Edge, Firefox, and Safari versions per the README
- MIT licensed with a documentation site and changelog
Trade-offs
- Requires a PeerServer for peers to find each other; the README points to a separate project for it
- The README notes a Parcel-related console warning when used with Webpack, described as non-critical
- Browser support is limited to listed versions; others are unsupported
How it compares
| Project | Stars | Type | Level | Updated | Best for |
|---|---|---|---|---|---|
| peerjs (this) | 13.5k | Library | intermediate | 8 months ago | Web developers adding real-time chat or file-style data exchange between browsers |
| socket.io | 63.2k | Library | intermediate | 1 months ago | Developers building live chat or real-time notifications in JavaScript or TypeScript |
| webtorrent | 31.5k | Library | intermediate | 5 days ago | Developers who want to add torrent downloading or streaming to a JavaScript web or Node.js app |
| feathers | 15.3k | Library | intermediate | 5 days ago | JavaScript or TypeScript developers building a web API |
| webtorrent-desktop | 10.1k | App | beginner | 6 days ago | People who want to stream torrent video without waiting for a full download |
| monaco-editor | 46.9k | Library | intermediate | 6 days ago | Web developers adding a code editing box to a browser app |
Stats synced from GitHub. The assessment above was drafted with AI from the project's README on 2026-10-29 and may miss recent changes — check the README before relying on a command. MIT licence: free to use, modify and distribute, including commercially, as long as you keep the copyright notice.