Android Developers Blog: Improving App Startup: Lessons from the Facebook App
Article Summary
Facebook's Android app serves 2.9 billion users monthly. Their startup optimization strategy cut bad starts by focusing on one counterintuitive metric.
Google's Android team partnered with Facebook engineers to document how they measure and optimize app startup performance. This collaboration reveals the metrics, targets, and specific techniques Facebook uses to deliver fast, reliable launches across billions of devices worldwide.
Key Takeaways
- Facebook targets 2.5 seconds for Time To Full Display, matching Web Vitals standards
- They measure bad starts: any launch over 2.5s OR with failed content/images
- reportFullyDrawn() API tells Android to prioritize work before that point
- Consistency beats speed: inconsistent performance frustrates users more than slower averages
- Fresh content may beat cached content: measure what users actually value
Critical Insight
Facebook prioritizes full content delivery over initial render speed, measuring complete user experience including network calls and image loads to drive meaningful improvements.
