Measuring App Performance with MetricKit
Article Summary
Ninikvatchantiradze from Teknasyon Engineering reveals why most iOS developers are measuring app performance completely wrong. If you're only testing locally or tracking basic CPU metrics, you're missing what's actually breaking your user experience.
Apple's MetricKit framework collects real-world performance data directly from users' devices, but many teams still rely on simulator testing and averages that hide critical issues. This guide breaks down the exact metrics that matter (hang rates, scroll hitches, thermal throttling) and shows how to integrate MetricKit in just three steps.
Key Takeaways
- Local testing misses real issues: crashes, freezes, battery drain users actually experience
- Hang rate over 250ms and scroll hitches directly kill UX and retention
- MetricKit integration takes 3 steps: import framework, register subscriber, implement protocol
- Peak memory usage and thermal state detect problems before they cause crashes
- Real data only available in TestFlight/App Store, not simulator or debug builds
MetricKit provides the real-world performance data you need to fix issues users actually experience, not just what shows up in your local tests.
About This Article
Most developers only track CPU and memory, which means they miss the issues that actually hurt users. When apps hang for more than 250ms or have scroll hitches, people notice. These problems drive uninstalls and tank App Store ratings.
Ninikvatchantiradze's MetricKit guide helps iOS teams collect real data from production. You get five metric categories: CPU and GPU, memory, hang time, battery and thermal issues, and network activity. The data comes directly from TestFlight and App Store builds, not from unreliable simulators.
Teams can now see which devices perform worst and compare metrics across iOS versions. This lets them focus on fixes that actually matter, like reducing hang rates and thermal throttling. The result is better retention because they're fixing the crashes and freezes that users experience in the real world.
