That Time Cloudflare Sneezed and the Internet Caught a Cold (November 18, 2025)

Remember that day in November 2025 when half your favorite websites just stopped working? You’d click a link, and instead of your feed, you’d get a weird error message. You’d refresh, check your Wi-Fi, and maybe even restart your phone, but nothing. For a few hours, it felt like a piece of the internet itself had just… vanished.

That wasn’t your imagination. On November 18, 2025, a huge part of the online world really did go dark. And the reason was a massive outage at a company called Cloudflare. If you don’t know who Cloudflare is, that is kind of the point. They are one of those invisible giants that makes the internet work. They are the backstage crew for the digital world. And on that day, they tripped over a cable and brought the show to a halt.

This is the story of that incident, told without the super technical jargon. Lets talk about what happened, why it broke so much stuff, and what it teaches us about the modern internet.

So, What Does Cloudflare Actually Do?

To understand why this was such a big deal, you need to know what Cloudflare’s job is. Imagine a popular nightclub.

The nightclub is your favorite website, like X (formerly Twitter) or Spotify. Now, imagine there is a single, huge front door that every single person has to walk through to get inside. That door has a team of bouncers. Their job is to check IDs, keep out troublemakers, and make sure the line moves smoothly.

Cloudflare is that bouncer, that traffic director, and the entire front door system for millions of websites. When you type a web address into your browser, your request often goes to a Cloudflare server first. Cloudflare checks if you are a real human or a malicious bot. It can block attacks, and it also stores a cached copy of the website to make it load faster for you.

Millions of companies, from tiny blogs to tech giants, pay Cloudflare to be their front door. So, when something goes wrong with Cloudflare, it is not just one club that closes. It is like every club in the entire city suddenly locked its doors at the same time.

The Morning It All Went Wrong

Inside Cloudflare, November 18 started like any other day. A team of engineers was doing some routine maintenance. It was the digital equivalent of changing a lightbulb or tightening a loose screw. They were updating the permissions on one of their important databases, which is basically a fancy filing cabinet for digital information.

This particular filing cabinet held the instructions for Cloudflare’s Bot Management system. This is the smart software that identifies bots. The engineers made the small change. It seemed to work. But they had accidentally set off a chain reaction.

Because of the new permissions, the system started generating a crucial configuration file with a major error. It was duplicating information. Think of it like writing a to do list:

Buy milk
Buy eggs
Buy bread

But because of the glitch, the list became:

Buy milk
Buy milk
Buy eggs
Buy eggs
Buy bread
Buy bread

This duplicated list, this “file,” started bloating to twice its normal size. And then, automatically, Cloudflare’s system sent this bloated, broken file out to every one of its thousands of servers around the world.

These servers are designed to read this file quickly. But when they tried to read this giant, messed up version, they could not process it. It was like trying to drink from a firehose. The software on each server choked, panicked, and crashed.

And just like that, the bouncers at the door were knocked out cold.

What You Saw: The Internet Grinds to a Halt

If you were online that morning, you witnessed the effects firsthand. Major sites like X, ChatGPT, Shopify, and Discord became inaccessible. Instead of content, you saw error messages like “500 Internal Server Error” or “Error 520.” These are just generic computer codes for “Something is very wrong back here, but we have no idea what.”

People flooded to other social media platforms and carrier networks to ask, “Is the internet down?” Websites like DownDetector, which track outages, saw a massive spike in reports from all over the globe. It was a digital domino effect.

The irony was that Cloudflare’s own customer dashboard, where clients would go to check the status of their services, was also down. Why? Because it used Cloudflare’s own security system to log in, and that system was broken. They had locked themselves out of their own control room.

The Scramble to Fix Everything

At first, the Cloudflare engineers were baffled. With so many systems failing simultaneously, their first thought was, “This must be a historic cyberattack.” They started looking for an enemy, a digital army that was overwhelming their defenses.

After some frantic investigation, they realized the truth. The problem was not an external attacker. It was an internal bug, a hidden flaw in their own code that had been triggered by the routine permission change. They were not under siege, they had accidentally shot themselves in the foot.

The fix, in theory, was straightforward.

Stop sending the bloated file.
Find a recent, good version of the file and send that out instead.
Restart all the servers so they load the good file.

But doing this across a global network is like trying to change the tires on a car that is speeding down the highway. It takes time and precision. They had to identify the root cause, halt the distribution system, push out the clean file, and then carefully reboot their core services. This was not a single switch they could flip, it was a delicate surgical procedure on the internet’s nervous system.

After several hours, the fix was in place. The good file was distributed, servers came back online, and slowly, the internet began to wake back up. Websites loaded, error messages vanished, and life returned to normal.

The Ripple Effect: A Wake Up Call

This outage did not just annoy people trying to scroll through social media. It caused serious problems for other companies that depend entirely on Cloudflare.

Take a service called Resend, for example. Resend helps other apps send emails. All of their internet traffic flows through Cloudflare. When Cloudflare went down, Resend was completely cut off from the world. Their own servers were fine, healthy, and ready to work, but no one could reach them because the only road to their building was closed. They were a perfectly functioning business with no customers because the front door was locked.

This was a major lesson in what tech people call “single point of failure.” Relying on one company for a critical service is a huge risk. After this incident, countless businesses started rethinking their infrastructure, looking for backup plans and alternative routes to ensure they would not be so vulnerable next time.

The Big Lesson: The Internet is Fragile

The Cloudflare outage of 2025 was not the first of its kind, and it will not be the last. Similar things have happened with other infrastructure giants like Amazon Web Services and Google. These events reveal a simple truth, the modern internet is both incredibly robust and surprisingly fragile.

It is robust because it can handle amazing amounts of traffic and data. But it is fragile because so much of it is built on top of a few key pillars. When one of those pillars wobbles, everything on top of it shakes.

Cloudflare was very open after the event. They published a detailed post mortem, explaining the exact sequence of events. They apologized and promised to learn from it. The core lesson was about humility. Even the most advanced systems, run by the smartest people, can be brought down by a small, unexpected bug.

For the rest of us, it was a reminder. The internet is not a magic, abstract cloud. It is a physical thing made of wires, servers, and code. It is built and maintained by people. And people, sometimes, make mistakes. Even the people who guard the door to the internet.

So the next time a website does not load, maybe give it a second. Someone, somewhere, might be having a very, very bad day at the office.