What is Fastly and what caused the internet to go down today?

Major websites around the world went down Tuesday morning due to an issue with a company that works to shore up the speed and reliability of the websites of its clients.

>> Read more trending news

Fastly, a company based in San Francisco, is a content delivery network (CDN), and helps it clients — which include Amazon, Google, media websites like The New York Times and social networks like Reddit — to keep their sites loading quickly and accurately.

A CDN works to make pages load on a user’s device quickly by using geographically distributed groups of servers that help reduce the distance between a server and a user.

So what happened on Tuesday?

A little before 6 a.m. ET, those trying to log onto the sites Fastly works with were getting error messages saying the site could not load.

At 5:58 a.m. ET, a notice was posted on the company website, saying “We’re currently investigating potential impact to performance with our CDN services.”

Websites such as PayPal, Twitch, Hulu and the British government’s main webpage all went down, according to The New York Times, which also saw its page disappear.

A Fastly spokesperson told the Times that the problem was caused by a disruption to Fastly’s systems that send website content from a server to individual users.

About an hour after the sites went down, Fastly issued another statement saying, “The issue has been identified and a fix has been applied.”

The sites came back online soon after that.

According to the Washington Post, Fastly said in an emailed statement that it was a “technical issue” and “not related to a cyber attack.”

The outage seemed to catch the eyes of investors, as major futures markets in the U.S. dipped sharply minutes after the outage. The stocks recovered by midday as stocks were up around 10 points at 1:30 p.m. ET.