Android Network Observability: Shedding Light on Performance Blind Spots
Article Summary
Shaurya Jaiswal from Slice reveals how his team cut app launch API calls from 28 to 12, improving startup time by 40%. The secret? A custom observability system that exposes what Firebase Performance Monitoring can't see.
Most Android network monitoring tools show you error rates and latency, but they miss the critical details: DNS lookup times, SSL handshake delays, carrier-specific issues, and which APIs are hammering your backend at launch. Slice Engineering built an in-house solution using OkHttp's EventListener to capture every millisecond of the network request lifecycle.
Key Takeaways
- Custom EventListener tracks DNS, SSL, connection, and transmission times per request
- Request tagging pattern attaches metrics object throughout entire lifecycle
- Heatmap visualization identified 28 launch APIs, reduced to 12 over 3 releases
- Carrier-specific DNS optimization cut lookup time from 230ms to 60ms (74% faster)
- Sample under 5% of users to get insights without analytics cost explosion
By building granular network observability into OkHttp and Retrofit, Slice reduced app startup time by 40% and identified carrier-specific performance issues that standard tools completely missed.
