Announcing Lottie 4.0 for iOS

Airbnb just solved one of mobile animation's biggest performance problems. Lottie 4.0 eliminates the CPU overhead that was causing animations to drop frames and freeze.

Lottie is Airbnb's open source library for rendering vector animations, used in thousands of apps. Cal Stephens from the Airbnb team explains how they rebuilt the iOS rendering engine from the ground up.

Key Takeaways

• New Core Animation engine eliminates 5-20%+ CPU usage during animation playback
• Animations now run smoothly at 60-120 fps even when main thread is blocked
• Switching to new engine actually reduced Airbnb's app launch time
• Core Animation rendering engine now enabled by default in Lottie 4.0
• Bonus: 2x faster animation decoding and dotLottie file support

The article includes side-by-side performance comparisons showing exactly how the old vs. new rendering engines behave under stress.