iOS App Performance
Article Summary
Monzo's iOS app got 60% slower over time, and their team structure was partly to blame. Here's how they fixed it and prevented it from happening again.
Monzo's engineering team shares a transparent postmortem on iOS performance degradation that affected launch times, scrolling, and tab switching. They detail the technical fixes, root causes, and organizational changes to prevent future issues.
Key Takeaways
- Switched to CocoaPods 1.6 beta with static linking, cutting launch time by 62%
- Optimized feed rendering and moved operations off main thread for 30% smoother scrolling
- Technical debt accumulated because no squad owned cross-cutting performance concerns
- Created dedicated performance squad and dashboards to track metrics continuously
- Android avoided these issues due to functional reactive programming and newer codebase
Critical Insight
Monzo reduced iOS launch time from 6.2s to 2.5s by addressing technical debt and creating explicit ownership for app performance.
