TikTok reduces code size by 58% and improves app performance for new features with Jetpack Compose

Building a path forward through strategic migration

By strategically adopting Jetpack Compose, TikTok was able to stay on top of technical debt, while also continuing to focus on creating great experiences for their users. The ability of Compose to handle conditional logic cleanly and streamline composition allowed the team to achieve up to a 78% reduction in page loading time on new or fully rewritten pages. This improvement was 20–30% in smaller cases, and 70–80% for full rewrites and new features. They also were able to reduce their code size by 58%, when compared to the same feature built in Views. The team has further shared a couple of learnings:

TikTok team’s overall strategy was to incrementally migrate specific user journeys. This gave them an opportunity to migrate, confirm measurable benefits, then scale to more screens. They started with using Compose to simplify the overall structure in the QR code feature and saw the improvements. The team later expanded the migration to the Login and Sign-up experiences.

The team shared some additional learnings:

While checking performance during migration, the TikTok team found that using many small ComposeViews to replace elements inside a single ViewHolder, caused composition overhead. They achieved better results by expanding the migration to use one single ComposeView for the entire ViewHolder.

When migrating a Fragment inside ViewPager, which has custom height logic and conditional logic to hide and show ui based on experiments, the performance wasn’t impacted. In this case, migrating the ViewPager to Composable performed better than migrating the Fragment.

Jun Shen really likes that Compose “reduces the amount of code required for feature development, improves testability, and accelerates delivery”. The team plans to steadily increase Compose adoption, making it their preferred framework in the long term. Jetpack Compose proved to be a powerful solution for improving both their developer experience and production metrics at scale.