Mobile App Launch Performance
Article Summary
Gonçalo Alvarez from Farfetch drops a hard truth: 86% of users uninstall apps after one use due to poor performance. Your launch time might be costing you customers before they even see your product.
This deep dive breaks down iOS app launch performance into its six critical components, from DYLD3 to first frame render. Alvarez explains why that first 400ms matters more than you think, backed by research showing 70% of users abandon apps within 11 seconds of waiting.
Key Takeaways
- Apple's guideline: first pixels must display within 400ms of launch
- Three launch types (cold, warm, resume) each require different optimization strategies
- Common culprits: obsolete SDKs, chatty network requests, and overcrowded launch sequences
- Six-stage launch process from dynamic linking through extended app-specific work
- Apple's framework: minimize work, prioritize correctly, and optimize ruthlessly
App launch performance directly impacts uninstall rates and app store ratings, making those first 400ms a critical business metric, not just an engineering concern.
About This Article
Farfetch realized that mobile app launch performance had become an important engineering concern that needed to be part of business decisions and strategic planning.
The team worked through several launch bottlenecks: slow server speeds, encrypted connections that weren't optimized for HTTP/2 and SPDY, problematic third-party libraries, and network latency.
Apple's framework offers three guidelines: minimize work by deferring tasks and moving blocking work off the main thread, prioritize with correct QoS, and optimize algorithms. Following these helps teams reach the ideal two-second launch time.
