X-Clacks-Overhead | hleb.dev

I am a big fan of Sir Terry Pratchett. His books influenced my sense of humor and the way I look at things, far beyond just fantasy literature. Some time ago, I added a small but meaningful detail to this blog – the X-Clacks-Overhead HTTP header.

This header is a reference to the “Going Postal” novel and the Clacks system. In short, it is a quiet way to say “GNU Terry Pratchett” – a signal that keeps his name moving through the network, not forgotten.

My blog is served with Cloudflare Pages. It supports custom HTTP response headers via a plain text _headers file placed in the root directory of your website, injecting headers according to the rules you define.

Here’s the relevant section from my _headers file:

/*
  X-Clacks-Overhead: "GNU Terry Pratchett"

That’s it – every request for static assets and HTML gets the header.

If you want to check it yourself, open browser developer tools → Network tab → inspect the response headers, or run:

It does nothing useful. It changes nothing about performance or functionality. But sometimes small, unnecessary things are exactly what make the internet better.