How We Improved Our 1Weather Android App Cold Startup Time by Over 70%
Article Summary
The 1Weather team slashed their Android app cold start time by over 70% and reduced slow starts by 24%. Here's the systematic approach that got them there.
Serving 100M+ users globally, the 1Weather engineering team knew every millisecond mattered for user retention. They used internal tooling (Raven Blitz) plus Android Studio Profiler to identify bottlenecks, then executed targeted fixes across their startup flow.
Key Takeaways
- Moved SDK initialization off main thread using ExecutorService
- Activated StrictMode to catch all I/O operations during startup
- Flattened launch screen layout and adopted lazy dependency injection with Hilt
- Removed legacy SDKs and shifted instrumentation logging to background threads
- Achieved 11% funnel improvement from app open to core value delivery
Critical Insight
Cold startup time dropped 70%+ (p90: 80ms to 60ms) and slow cold starts decreased 24.89%, putting 1Weather 6% ahead of industry peers.
