5 Mobile App Performance Metrics to Watch and Why
App stability is crucial, but it’s only one measure of app quality. Crashes aren’t telling you everything—there are other reasons for early app terminations and user abandonment. While crashes tend to quickly alienate users, slow performance is the less-obvious drag on long-term app usage. It's essential for developers to monitor how long a user waits at launch, between screen transitions, and after performing a request. In this post, we'll highlight 5 often-overlooked metrics for app performance.
- App launch
- UI responsiveness
- Network performance
- Screen loading
- Custom traces
App launches drive first impressions of mobile app quality. To the end user, launch speed is a first indicator of the overall quality of your app and sets expectations for performance. App launches remain important throughout the entire user lifetime, as repeat slow launches impact long-term retention. To get the full picture, monitor all launch types and first landing screen loading times.
- Cold launch: 2–4 seconds
- Warm launch: 2-3 seconds
- Hot launch: 1–1.5 seconds
Don’t leave them hanging—users are conditioned to expect quick and accessible experiences, and they may abandon your app or view your brand unfavorably if they encounter slow or hanging UI performance. You can assess UI hangs by comparing your app’s delay in responding to a user input to the total amount of time they spend on a certain screen. This metric is frequently ignored, but has a major impact on user experience.
- Target: <100ms
- Hang: 250ms
Network requests contribute heavily to app speed and responsiveness. What a user may perceive as a hang or error may actually be a slow or failed network call. Many mobile teams monitor server-side performance, but they’re only capturing half of the user experience. Tracking client-side requests and their response times is key to fully understanding network performance.
- Target: 1 second
Optimizing screen transitions and content loading times helps ensure a smooth, uninterrupted user experience. Instabug’s App Performance Monitoring detects delays in content loading stages. Loading times can vary depending on the type and amount of content—for longer wait times, use progress indicators to manage user expectations.
Every app is built differently; you’ll need to assess custom client-side logic and see how long it takes to execute specific traces in your app. Tracking individual traces in addition to overall performance will help you identify and resolve issues faster, quickly stacking targeted improvements.
- Target: 2 seconds
Five performance metrics, one way to measure them
Apdex (Application Performance Index) is an industry-standard metric used to track and measure user satisfaction based on performance; a combination of speed and stability, factoring in multiple performance inputs. Scores range from 0 to 1, with 1 being perfect. Apdex simplifies quantifying performance and allows your team to align around a standardized quality metric that can be used to set targets, create performance alerts, and monitor changes over time.
Apdex scores can be more useful than traditional KPIs like wait times because they represent a holistic view of app performance and can be calibrated to specific use cases. If you’re using Instabug, for example, you can add and subtract key metrics, variables you want to contribute to your overall Apdex score. This allows you to set performance thresholds that are specific to your app, rather than aiming for general benchmarks. You can use Apdex for overall app performance as well as individual metrics and transactions.
Related reading: What Is Apdex? All About the Metric That Measures App Performance
App performance resources:
- App Launch Optimization: How to Resolve Slow Startup Times
- Mobile App Network Performance Monitoring and Debugging Guide
- Understanding Cold, Hot, and Warm App Launch Time
- How Often Should You Update Your Free Mobile App?
Instabug empowers mobile teams to maintain industry-leading apps with mobile-focused, user-centric stability and performance monitoring.