What is this?
Socket.IO is a library that enables bidirectional, low-latency, real-time communication between a Node.js server and clients such as browsers or mobile apps.
Socket.IO is a library that enables bidirectional, low-latency, real-time communication between a Node.js server and clients such as browsers or mobile apps.Is this a standalone server or a library I add to my existing app?It is a library: you install the socket.io package on your Node.js server and the matching socket.io-client package in the browser or app to connect them over the network.
It is a library: you install the socket.io package on your Node.js server and the matching socket.io-client package in the browser or app to connect them over the network.How do I get it running?Rather than giving install steps inline, this README points you to the official Socket.IO documentation for setup and usage.
Rather than giving install steps inline, this README points you to the official Socket.IO documentation for setup and usage.Do I need Node.js to run the server side?Yes, the server package is built to run on Node.js, and the project itself is written in TypeScript.
Yes, the server package is built to run on Node.js, and the project itself is written in TypeScript.What transport actually powers the connection under the hood?The repo's CI workflows show it's built on separate 'engine.io', 'engine.io-client', and 'engine.io-parser' sub-projects, which handle the underlying transport (WebSocket with fallback) beneath the Socket.IO API.
The repo's CI workflows show it's built on separate 'engine.io', 'engine.io-client', and 'engine.io-parser' sub-projects, which handle the underlying transport (WebSocket with fallback) beneath the Socket.IO API.Can it scale across multiple server instances?Yes, the codebase ships a dedicated 'socket.io-adapter' component (visible in its CI config) used to broadcast events to clients connected through different server processes when scaled horizontally.
Yes, the codebase ships a dedicated 'socket.io-adapter' component (visible in its CI config) used to broadcast events to clients connected through different server processes when scaled horizontally.Why use Socket.IO instead of a raw WebSocket connection?Socket.IO layers automatic reconnection, fallback transports, and an event-based API on top of raw WebSockets, features plain WebSocket connections don't give you out of the box.
Socket.IO layers automatic reconnection, fallback transports, and an event-based API on top of raw WebSockets, features plain WebSocket connections don't give you out of the box.What is engine.io?Engine.io is the lower-level transport module Socket.IO is built on; the repo's CI configs show engine.io, engine.io-client, and engine.io-parser as maintained sub-projects.
Engine.io is the lower-level transport module Socket.IO is built on; the repo's CI configs show engine.io, engine.io-client, and engine.io-parser as maintained sub-projects.Where do I ask usage questions instead of filing an issue?GitHub issues are reserved for bugs and feature requests; for usage help the maintainers point to the docs, a troubleshooting guide, Stack Overflow, or GitHub Discussions.
GitHub issues are reserved for bugs and feature requests; for usage help the maintainers point to the docs, a troubleshooting guide, Stack Overflow, or GitHub Discussions.Does it support broadcasting to clients across multiple servers?Yes, via the socket.io-adapter package, which handles broadcasting events to sockets connected to different server instances, e.g. in a horizontally scaled deployment.
Yes, via the socket.io-adapter package, which handles broadcasting events to sockets connected to different server instances, e.g. in a horizontally scaled deployment.What are similar projects?socket.io-client, centrifugo, pomelo, tornado, websocket, feathers, sails, chat
socket.io-client, centrifugo, pomelo, tornado, websocket, feathers, sails, chatWhich topics is it in?socket-io, websockets, realtime, scalability, messaging, chat, node, websocket, http, browser, backend, networking
socket-io, websockets, realtime, scalability, messaging, chat, node, websocket, http, browser, backend, networking