Netflix : FAST.com Now Measures Latency and Upload Speed

A little over two years ago, we launched FAST.com - a free, fast, and simple way for people to check the speeds they're getting from their internet service provider. Since then, the site has experienced incredibly strong organic growth. In fact, usage of FAST.com has doubled over the past seven months, * and the site has now generated more than half a billion speed tests from around the world.

We've heard from some FAST.com users that they crave more information about their internet connection. That's why today, we're adding the ability to measure connection latency and upload speed. Upload speed measures the speed of the connection for uploading data from a user's device to the internet. Latency - which refers to the time it takes for data to travel from a user's device to the server and back - will be measured on both unloaded and loaded connections. Unloaded latency measures the round-trip time of a request when there is no other traffic present on a user's network, while loaded latency measures the round-trip time when data-heavy applications are being used on the network.

For example, let's say you're playing a game online on your computer. If you're the only user on the network, then the time between your gaming action (like moving a mouse or clicking it) and the response from the gaming server will approximately match the unloaded latency measurement. However, if someone else is streaming a movie, backing up photos or performing other data-intensive tasks on the same network at the same time, your gaming response time would correspond to the loaded latency measurement. Ideally, those two values for unloaded and loaded latency should be close to each other. If not, that might explain your poor experience with latency sensitive applications (like gaming, video calls or web surfing) under heavy network usage, and you may want to check your home network setup (bufferbloat.net has useful recommendations) or consult with your ISP.

We all want a faster, better internet, yet internet speeds vary greatly and can be affected by other users on your network, or congestion with your internet service provider. We're adding these new measurements to FAST.com so that consumers will have a more comprehensive view of their internet connection speed at any given time.

As FAST.com grows, we'll continue to listen to feedback from our users to ensure that the tool is useful and valuable. And no matter what, we'll always keep the design of FAST.com clean and ad-free.

You can check your upload speed and latency at FAST.com now, and feel free to share the results on Facebook or Twitter.

- Sergey

Sergey Fedorov is a senior software engineer on the content delivery team.

*FAST.com reached the quarter billion speed tests milestone in November 2017. The site generated another quarter billion speed tests from December 2017 - June 2018.