Skip to main content
Version: 2.x


Can I use wildcards in events?

Not in Socket.IO directly, but check out this plugin by Hao-kang Den. It provides a Socket.IO middleware to deal with wildcards.

Prevent flooding from single connection?

Limit number of events by IP, uniqueUserId or/and with rate-limiter-flexible package.

Socket.IO with Apache Cordova?

Take a look at this tutorial.

Socket.IO on iOS?

Take a look at

Socket.IO on Android?

Take a look at

Usage with express-session

const express = require('express');
const session = require('express-session');
const app = express();

const server = require('http').createServer(app);
const io = require('')(server);

const sessionMiddleware = session({ secret: 'keyboard cat', cookie: { maxAge: 60000 }});
// register middleware in Express
// register middleware in Socket.IO
io.use((socket, next) => {
sessionMiddleware(socket.request, {}, next);
// sessionMiddleware(socket.request, socket.request.res, next); will not work with websocket-only
// connections, as 'socket.request.res' will be undefined in that case

io.on('connection', (socket) => {
const session = socket.request.session;

const port = process.env.PORT || 3000;
server.listen(port, () => console.log('server listening on port ' + port));