Performance Tools

Keep-Alive Checker

Check whether a website lets browsers reuse one connection for several requests.

Not sure what to enter? Try an example: wikipedia.org

Free & instant No signup How to use FAQ

Enter a URL to see whether the server supports persistent (keep-alive) connections.

What is HTTP Keep-Alive?

Keep-Alive (persistent connections) lets a browser reuse one connection for several requests instead of opening a new TCP and TLS connection for every file. That saves round trips on each page load. HTTP/2 and HTTP/3 connections are always persistent.

How to check Keep-Alive support

Enter the domain in the box above.
Click Check Keep-Alive.
Confirm persistent connections are supported.
If not, enable keepalive in your web server, or serve the site over HTTP/2.

Related checks

To check for HTTP/2, use the HTTP Version Checker.
For a combined speed overview, use the Performance Health Score.

Keep-Alive lets a browser reuse one connection for many files, which matters most on slow mobile networks. If it is off, it is usually a server setting - JustChecker tracks response times after you change it.

Frequently Asked Questions

Opening a connection - especially an HTTPS one - takes several round trips. Reusing it for every image and script on a page saves that time again and again.

HTTP/2 and HTTP/3 always reuse connections, so it's built in. The check matters most for servers still on HTTP/1.1.

It is on by default in Nginx and in Apache (KeepAlive On). If it's off, check your server config or ask your host.

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