By Raymond Endres, Facebook VP of Engineering, Messenger
When Messenger first became its own app in 2011, our goal was to build a messaging experience rich with features. We added video calling, GIFs, location sharing and more. And while people enjoyed these features, the app became harder to navigate and the architecture became increasingly complex.
People turn to messaging apps throughout the day to stay in touch with the people they care about so it’s important the app loads quickly and is simple to use. On the heels of Messenger 4, we started a journey to simplify and redesign Messenger, internally called Project LightSpeed, and now we’ve rebuilt the iOS app from the ground up. Starting today, we are rolling out a faster, smaller and simpler Messenger on iOS over the next few weeks. Messenger will load twice as fast* and will be one-fourth its original size.
We know how much speed and reliability matter when you’re having conversations with family and friends throughout the day, so we redesigned the app with those in mind.
Faster: A faster start time may not matter as much if you only open an app once or twice a day to play a game or watch a movie, but it makes a huge difference when you open an app many times a day to respond to messages from the people who matter most.
Smaller: A smaller app means Messenger starts, downloads and updates faster for everyone, including people who use the app on older devices or in areas with lower connectivity where every kilobyte counts.
Simpler: We’ve streamlined the app while keeping it rich with features and making it easier for our engineers to build better experiences. For example, we’ve reduced the contact list from 40 versions to one that works consistently across the app. This not only helps with the cognitive load for people, but it also means engineers don’t need to build new experiences from the ground up.
Simplifying our iOS app to make it faster and smaller was no easy feat when more than 1 billion people rely on Messenger. We reduced Messenger’s core code by 84% — going from more than 1.7 million lines of code to 360,000 — and we rebuilt our features to fit a new, simplified infrastructure. Fewer lines of code makes the app lighter and more responsive, and a streamlined code base means engineers can innovate more quickly. As part of the rebuild, a few features will be temporarily unavailable, but we’re working to bring them back soon.
LightSpeed not only makes the app faster, smaller and simpler for our users, it also lays the foundation to fulfill our vision for private messaging and interoperability across apps, allowing us to scale our messaging experience in the future.
You can read more about how we rebuilt Messenger in our Engineering blog.