Node.js http.server.keepAliveTimeout Property

Last Updated : 23 Jul, 2025

The http.server.keepAliveTimeout is an inbuilt application programming interface of class Server within http module which is used to get the number of milliseconds of inactivity a server needs to wait for additional incoming data.

Syntax:

server.keepAliveTimeout

Parameters: This API does not accept any argument as a parameter.

Return Value: This method returns the number of milliseconds of inactivity a server needs to wait for additional incoming data.

Example 1: Filename: index.js

JavaScript

// Node.js program to demonstrate the
// server.keepAliveTimeout property

// Importing http module
const http = require('http');

// Setting up PORT
const PORT = process.env.PORT || 3000;

// Creating http Server
const httpServer = http.createServer(
    function (request, response) {

        // Getting the reference of the
        // underlying socket object
        // by using socket API
        const value = response.socket;

        // Display result
        // by using end() api
        response.end("Socket buffersize : "
            + value.bufferSize, 'utf8', () => {
                console.log("displaying the result...");

                // Closing server
                // by using close() api
                httpServer.close(() => {
                    console.log("server is closed")
                })
            });
    });

// Listening to http Server
// by using listen() api
httpServer.listen(PORT, () => {
    console.log("Server is running at port 3000...");
});

// Getting keep alive timeout value
// by using keepAliveTimeout api
const v = httpServer.keepAliveTimeout

// Display the result
console.log('keep alive time out value :-' + v)

Run the index.js file using the below command:

node index.js

Console Output:

keep alive time out value :-5000
Server is running at port 3000...
displaying the result...
displaying the result...
server is closed
server is closed

Browser Output: Paste the localhost address http://localhost:3000/ in the search bar of the browser.

Socket buffersize : 0

Example 2: Filename: index.js

JavaScript

// Node.js program to demonstrate the
// server.keepAliveTimeout property

// Importing http module
const http = require('http');

// Request and response handler
const http2Handlers = (request, response) => {

    // Getting the reference of the
    // underlying socket object
    // by using socket API
    const value = response.socket;

    // Display result
    // by using end() api
    response.end("Socket local address : "
        + value.localAddress, 'utf8', () => {
            console.log("displaying the result...");

            // Closing server
            // by using close() api
            httpServer.close(() => {
                console.log("server is closed")
            })
        });
};

// Listening to http Server
// by using listen() api
let httpServer = http.createServer(
    http2Handlers).listen(3000, () => {
        console.log("Server is running at port 3000...");
    });

// Getting keep alive timeout value
// by using keepAliveTimeout property
const v = httpServer.keepAliveTimeout

// Display the result
console.log('keep alive time out value :-' + v)

Run the index.js file using the below command:

node index.js

Console Output:

keep alive time out value :-5000
Server is running at port 3000...
displaying the result...
displaying the result...
server is closed
server is closed

Browser Output: Paste the localhost address http://localhost:3000/ in the search bar of the browser.