Cloudflare meme. Courtesy image
By REBECCA RUTHERFORD
Los Alamos
For the Los Alamos Daily Post
What happened?
On Nov. 18, 2025, Cloudflare — a firm that helps power and protect a big chunk of the internet — had a major outage. Websites and services you use like ChatGPT, X, Spotify and more were either unavailable or showing error messages. Ruh roh raggy!
- Cloudflare uses a “feature file” that helps its system spot bots and protect websites.
- A change was made to a database system, which caused that feature file to double in size, beyond what the system expected or could handle.
- Because the file was too big, the software crashed. That crash cascaded into big parts of Cloudflare’s network being unable to route traffic properly.
- Cloudflare emphasised it was not caused by a cyber-attack or malicious activity.
So what the heck is Cloudflare? Cloudflare is an internet services company that provides a global network to make websites faster and more secure, acting as an intermediary between a website and its visitors. This allows it to route traffic through its network to protect against attacks and improve performance through services like its content delivery network (CDN). This means when Cloudflare has an outage, it can temporarily affect the websites that use its services, leading to an outage for the websites. This is what happened on Tuesday.
What was the impact?
- For hours, many websites and apps you rely on either didn’t load or showed “server error” messages. Not a great start to the traditional “Black Friday Week”.
- Because Cloudflare supports a huge portion of internet traffic, one internal file mistake had ripple effects globally.
- Cloudflare acknowledged the problem, apologised and said they would make changes so this kind of thing happens less.
Why it matters for everyday users
- It shows how much of the web depends on a few infrastructure companies. If one of those has a failure, we all feel it, similar to the Amazon Web Services outage last month.
- Even though it wasn’t a cyber attack, a routine technical change still triggered big disruption. It doesn’t have to be malicious to have big, negative consequences; it can be as simple as Bob the intern having a bad day.
- If you run a website or app, this is a reminder that building redundancy and backup plans (what if your main traffic handler fails?) is important.
Cloudflare meme. Courtesy image
The takeaway
A tiny-seeming glitch — a file doubling in size — turned into a global web disruption. It’s a cautionary tale that even large systems with complex safeguards can fail from simple oversights. For all of us who click links, scroll feeds or wait for apps to load: there’s a whole invisible scaffolding beneath the internet, and when it falters, we notice. This is just one of several incidents this year that have disrupted services worldwide, reminding us how interconnected we really are. All it takes to take out large swaths of the internet is… a single file doubling in size. Yikes!
What can you do as an everyday user? Not much to be honest, but next time a site isn’t loading right and you aren’t sure what’s going on, go to downdetector.com and check to see if there are any noted outages for whatever service is having issues. Not gonna lie, this site is great for telling me if it’s an issue with my computer, or with a company’s servers. And if you figure out it’s a huge outage, you can go tweet about it and let everyone else know!
Editor’s note: Rebecca Rutherford works in information technology at Los Alamos National Laboratory.