3 Techniques We Used to Improve Skyscanner for iOS Performance
Article Summary
Skyscanner's iOS team discovered their app was lagging on nearly half their user base. The culprit? Testing only on high-end devices.
The Skyscanner engineering team shares how they systematically improved iOS app performance using measurement-driven optimization. Their approach focused on identifying bottlenecks that affected users on older devices like the iPhone 5, which represented 10% of their user base.
Key Takeaways
- Removed unnecessary accessibility label calculations for 8.9% performance boost
- Implemented date cache to eliminate redundant calculations, gaining 3.2% improvement
- Used Instruments profiler to identify main thread bottlenecks causing UI lag
- Built custom FPS monitoring tool to track real-world performance during testing
- Improved smooth navigation from 61% to 97.47% of users maintaining 30+ FPS
Through targeted caching and measurement-first optimization, Skyscanner increased the percentage of users experiencing smooth 30+ FPS navigation from 61% to 97.47%.
About This Article
Skyscanner's flights result page was recalculating accessibility labels for all 1000+ results even when users hadn't enabled the accessibility feature, wasting CPU resources on the main thread.
The team added a check to skip accessibility label generation for users who hadn't turned on the feature, which stopped the unnecessary string calculations.
CPU time spent on localized resources dropped from 13.5% to 4.6%, resulting in an 8.9% performance improvement overall.