Web services provider Cloudflare got hit by an outage on Tuesday, disrupting access to many websites and services including OpenAI, Spotify, X, Grindr, Letterboxd and Canva.

Cloudflare is a cloud services and cybersecurity company based in San Francisco that is used by approximately 20% of all websites, according to W3Techs. It’s one of a handful of services, along with Amazon Web Services, CrowdStrike and Fastly (all of which have experienced major outages in the past few years) that you might never have heard of, but that provide essential internet infrastructure.

The bulk of sites and services impacted by Tuesday’s outage, which began around 3.30 a.m. PT, seemed to recover within three hours of Cloudflare going down. It’s likely that some continue to be affected, and may still experience difficulties throughout the day. At the time of writing, Cloudflare was still issuing updates about the incident to its system status page.

Cloudflare hasn’t yet said what caused the outage, but has promised to conduct a full investigation.

Which sites and services were impacted?

Cloudflare has a massive range of clients across the internet, ranging from websites that are household names to smaller services you might not have heard of. Due to its size, when it went down, it took many of those sites and services with it.

Among those affected by the outage was Downdetector, which is where most people go to report problems when services are offline. (Downdetector is owned by the same parent company as CNET, Ziff Davis.)

Now that it’s back up and running, Downdetector says that it received over 2.1 million reports during the outage period. Over 435,000 of these came from the US, with the UK, Japan and Germany appearing to be the countries that were next most affected.

Most of the reports pertained to Cloudflare, but other affected companies also received a significant number of reports. They include X (320,549 reports), League of Legends (130,260 reports), OpenAI (81,077 reports), Spotify (93,377 reports) and Grindr (25,031 reports).

How did the outage unfold?

Cloudflare first acknowledged the outage at 3.48 a.m. PT. The company issued a statement on its system status page saying that it was aware of the problem. 

«Cloudflare is aware of, and investigating an issue which impacts multiple customers: Widespread 500 errors, Cloudflare Dashboard and API also failing,» it said. «We are working to understand the full impact and mitigate this problem. More updates to follow shortly.»

At 5.09 a.m. PT, the company said the issue had been identified and a fix was being implemented. In the subsequent hours, errors began to drop and services gradually came back online.

Cloudflare added at 9.14 a.m. PT that most services had returned to normal. «A full post-incident investigation and details about the incident will be made available asap,» it said.

Is the internet stable and reliable?

The Cloudflare outage comes just one month after Amazon Web Services went down, causing havoc across the internet. The AWS outage affected sites including Reddit, Snapchat, Roblox and Fortnite, sparking many to ask whether having such huge swathes of the internet reliant on a few centralized services is sensible or safe.

Major outages are also highlighting concerns about our growing reliance on AI — in particular the fragility of the infrastructure AI relies upon to function every day.

«The most dominant platform did not buckle because of simultaneous queries or the release of a new competitive model, but because of a problem with Cloudflare, a web security and performance provider,» said Sarah Kreps, director of the Tech Policy Institute at Cornell University. «The issue exposes the reality that this multi-billion, even trillion dollar investment in AI is only as reliable as its least scrutinized third party infrastructure.»