Cloudflare is down. Why this internet service provider you’ve never heard of is so important

Cloudflare went down today (November 18), disrupting access to some of the biggest websites around the world, including X, Letterboxd and ChatGPT, and leaving millions of people frustrated. The company said it is aware that it is facing widespread errors and that it is working to resolve them. But what do we know about Cloudflare? Why is it so important?