One Activity to Rule Them All: Reducing Crashes in the Etsy App

Etsy was getting 1,000 Out of Memory crashes per day on Android. The culprit? A navigation architecture from 2012 that couldn't handle modern browsing behavior.

The Etsy Android team tackled their top crash cause by migrating from a one-Activity-per-screen architecture to a single-Activity design with Fragments. They broke the migration of 40 Activities into three milestones, A/B testing each phase to measure business impact.

Key Takeaways

• OOM crashes dropped 60% (from 1,000 to 400 daily) after first milestone
• Single Activity with Fragments destroys Views on backstack, drastically reducing memory footprint
• FragmentLifecycleCallbacks pattern elegantly handles shared screen elements across all screens
• Conversion rate increased 1.5%, GMS per buyer up 1.1% in initial experiment
• Migration enabled new features like separate backstacks per bottom nav tab

The interface decoration pattern they used for managing shared screen elements is a clever solution worth stealing for your own Fragment migrations.