Have you ever wondered if a website could whisper secrets behind the scenes? Turns out they can, and some web developers are using those secrets to silently honor and memorialize those who have died.
Terry Pratchett’s Discworld series is easily one of my all-time favorites. It’s a setting that constantly delivers sharp humor and such a delicious satirical mirror to our own world. But Pratchett’s writing has stretched way beyond the pages of this (albeit lengthy) book series, from TV shows to fan creations. He even inspired quiet, touching way of honoring the dead built directly into the fabric of the internet itself.
Across the web, some websites silently transmit the names of people they wish to honor inside of their HTTP headers. This system was inspired by a fictional communications network in Pratchett’s Discworld setting: the clacks.
Let’s take a look at what the clacks are, how the x-clacks-overhead HTTP header works under the hood, and look at a Chrome extension I built to make it easy to spot these hidden memorials while you browse.
If you want to skip ahead and try the free extension out right away, you can find it on the Chrome Web Store at X-Clacks-Overhead Detector extension for Chrome browsers. It gives you a popup whenever you land on a website using the memorial header, and lets you know whose memory is being honored.
The Clacks, Discworld’s Steampunk Internet
First introduced in Pratchett’s novel The Fifth Elephant and further expanded in Going Postal, the clacks is essentially Discworld’s version of telecommunications. Think of a long chain of semaphore towers mashed together with an early version of the telegraph. It’s a system that brought rapid information exchange to a fantasy world where speed of communication is usually limited by the speed of a fast horse.
Each clacks tower is a simple structure topped with a complex arrangement of mechanical shutters and lamps. Clacks operators use coded signals to relay messages up and down the network. Picture a giant, mechanical, steampunk-style telegraph system and you’ve pretty much got it.
But of course, since it was created by Sir Terry Pratchett, the clacks has more to its story than just a cool invention in a fantasy world. The story around this technology touches on the ideas of corporate greed and how people cope with rapid technological progress, but there’s more depth to it.
The GNU Code
Clacks operators pass messages around using a semaphore-style code, rapidly flashing messages up and down the line of towers. Part of that process involves a message’s “overhead,” some administrative codes that might affect how a message is treated.
Most notably is the GNU, a specific operational code that essentially translates to “keep sending this message on, don’t log it, and once it reaches the end of the line, turn it around and send it back again.” This means that any messages that include this GNU code will echo forever up and down the line.
The book Going Postal includes the first instance of this code being used to memorialize someone who has passed. After clacks inventor Robert Dearhart’s son John dies in a tower accident, Robert sends out the signal GNU John Dearhart into the network. As long as the towers keep passing messages, John’s name stays forever in motion.
It’s a beautiful concept that’s always stuck with me, illustrated by the phrase: “a man is not dead while his name is still spoken.” As long as one’s name travels the clacks, they’re never truly gone.
GNU Inspiring Tech Savvy Fans
It didn’t take long for tech-savvy Pratchett fans to realize that our modern web architecture has some similarities to the clacks network… and might be used to similarly memorialize people. Our servers endlessly route data across the globe, they pass messages back and forth every millisecond.
Some developers decided to bring Pratchett’s fictional tribute into our actual internet framework using a subtle, omnipresent piece of web browser architecture: HTTP response headers.
Response Headers as Clacks Overhead
Every time your browser loads a webpage, a quick behind-the-scenes conversation happens between your device and the website’s host server. Your browser asks for data, and the server sends it back alongside a set of “headers.” You can think of headers as invisible Post-it notes attached to the data’s envelope, holding technical details like server types, caching rules, content formats, etc.
Headers are “kay-value pairs,” consisting of a header’s name (the key) and the value that’s been assigned to it.
Ordinarily these headers are something you as the user would never see, just purely technical parameters. But custom headers can also be created and allow developers to add whatever key-value pairs they need.
Enter the x-clacks-overhead header.
By adding a header of x-clacks-overhead: GNU Terry Pratchett (or the name of any other honored dead you wish to memorialize) to a web server’s configuration, developers ensure that every single time someone loads a page on their site this name is silently transmitted across the network.
The header doesn’t change page design, it doesn’t appear on the screen. It simply echoes through the wire with every page served.
How to Spot These Hidden Messages
Because these headers live in the background by design, you won’t spot them just by visiting a website they’re used on… unless you know where to look or have a tool that shows them to you!
Method 1: Using Browser Developer Tools
- Right-click on any webpage (you can use graycastlepress.com as an example!) and select “Inspect” or “Inspect Element”
- Go to the “Network” tab
- Reload the page and click on the first item (usually the page URL)
- Look for “Response Headers” and find
x-clacks-overheadin the list if it exists for the current website
Method 2: The X-Clacks-Detector Extension for Chrome
If opening the Developer Tools on every website you visit sounds unrealistic, there are a few Chrome extensions available that can help surface these memorials. I built one myself as a fun project, a lightweight extension that does the investigation for you.
When you land on a site that includes the x-clacks-overhead header, the X-Clacks-Overhead Detector extension shows a (easily dismissable) popup and includes the name of who is being memorialized. It’s a seamless way to discover this quiet, hidden layer of the web while you browse around.
Leaving a Legacy in the Background Noise
I’m always thrilled when I get to see people taking inspiration from creative work like Pratchett’s Discworld, especially when they’re so thoughtful. Reading Going Postal, appreciating the concept of the clacks, and thinking “Hey, I could probably build that into a website’s HTTP response headers” is the exact kind of clever crossover between creative fiction and real world tech that gets me fired up.
The x-clacks-overhead header is at once a fun easter egg for Discworld fans and a living tribute where our beloved fantasy fiction directly shapes the real world. It shows how fandom, when channeled creatively, can leave a lasting mark on the tools we use every single day.
Next time you’re surfing the web (geez, does anyone even say that anymore 👴), remember that just under the surface of the pixels and CSS of every website you visit, and invisible memorial to someone’s honored dead might be echoing through the connection, keeping their name alive in the background noise of the internet.
Graycastle Press is Luke Miller
Building games, homebrew, modules, and digital tools for the tabletop community and beyond with a unique brand of creativity and sense of humor. Publisher of the bestselling solo worldbuilding roleplaying game Journey.
Specializing in games that offer new methods of engaging with your creative work. Go on an adventure and return with the choicest loot: fresh ideas and inspiration. Use it to add even more spark to the things you build.