`app.listen()`

Binds and listens for connections on the specified host and port.

Since Express 4 Spec ↗

Syntax

app.listen([port[, host]][, callback])

Parameters

Name	Type	Required	Description
`port`	`number`	No	The TCP port to listen on.
`host`	`string`	No	The interface to bind.
`callback`	`function`	No	Invoked once the server is listening.

Returns

http.Server — The underlying Node HTTP server.

Examples

const app = express();

app.listen(3000, () => {
  console.log('listening on http://localhost:3000');
});

Output

listening on http://localhost:3000

const server = app.listen(process.env.PORT || 3000);

process.on('SIGTERM', () => {
  server.close(() => console.log('shut down cleanly'));
});

Output

shut down cleanly

Notes

Returns the Node `http.Server`, so you can call `server.close()` for graceful shutdown or attach Socket.IO. For HTTPS or HTTP/2 create the server manually with `http2.createSecureServer(app)` instead.