I’m a bit of a Facebook skeptic, but it’s really amazing that they had the guts to actually completely rewrite their Messenger app for iOS. That is such a gigantic effort that it basically doesn’t ever happen with popular apps at big companies. So kudos to Facebook for actually making that happen. 👉 Yay, Facebook! 🤷🏻‍♂️

👉 Project LightSpeed: Rewriting the Messenger codebase for a faster, smaller, and simpler messaging app

This post explains some of the design and architecture decisions they made. It’s interesting that Facebook, the company that invented the cross-platform React Native framework, went full native when rewriting their own app. In fact, one of their key principals in the rewrite was “Use the OS”.

While UI frameworks can be powerful and increase developer productivity, they require constant upkeep and maintenance to keep up with the ever-changing mobile OS landscape. Rather than reinventing the wheel, we used the UI framework available on the device’s native OS to support a wider variety of application feature needs.

They also use SQLite to create a sort of table-driven local business logic layer a custom platform “to orchestrate all access to the database, including queued changes, deferred or retriable tasks, and for data sync support.”

This is an example that all of us mobile engineers can take to our managers and demand a rewrite now! (Kidding / not kidding 🤓)

Via iOS Dev Weekly.