In order to make sure another billion people can connect using Facebook, the platform needs to design features of the product that work seamlessly regardless of mobile network and device. What this means for the News Feed team is making sure people can load and scroll through News Feed on any connection speed. They've worked on a few updates recently to improve the experience so it works seamlessly and quickly for people in all parts of the world.

Taking connection speed into account

There are many factors that they take into account in News Feed to make sure users are seeing the most relevant stories to them - even the type of device you're on or the speed of your mobile network or WiFi connection. Taking this into account helps to determine what kinds of stories to show you in News Feed. For example, if you are on a slower internet connection that won't load videos, News Feed will show you fewer videos and more status updates and links.

In order to simplify the way they distinguish between different types of networks, they have developed an open-sourced Network Connection Class, which is a way for the News Feed team to determine how fast your connection is. With recent updates, they can now start retrieving more stories and photos while you are reading News Feed on slower connections to make sure stories are always available as you keep scrolling. So if you are reading a post from your friend about their weekend, but doing so on a slower connection, Facebook will load more stories while you're reading so they are ready for you when you're done reading that post.

Prioritising which stories to load

If you are on a poor internet connection and your News Feed is loading slowly, Facebook will first download the story you're currently looking at, rather than download a series of News Feed stories. For example, if you are looking at a photo your friend posted that isn't fully downloaded, Facebook will prioritise that photo overloading a story below it, so you can see the most important photos you're viewing as quickly as possible.

Facebook is also investing in the best image formats for photo loading. They recently moved to a progressive JPEG photo format which allows them to start showing lower-quality versions of photos while they're still downloading, so you can see some of the photo instead of nothing. This lowers the amount of data required to send photos to be loaded, and speeds up the wait time for photos. Facebook made this change for iOS at the beginning of the year and now use the same technology on both iOS and Android.

Showing you stories when on particularly poor connections

Sometimes Facebook is unable to load any new News Feed stories if a connection is particularly congested or of poor quality. Users have said that when they visit News Feed they'd rather see stories that may have loaded on a previous visit than not see any stories at all. So now when you leave News Feed and then come back again on a bad connection, it will display previously downloaded stories. You can scroll down and see stories from your previous visit to News Feed until you are able to connect again to a mobile network.

Even though Facebook loads stories from previous visits to News Feed, it doesn’t re-retrieve these stories that you have already seen, so you aren't wasting more data.