Monzo boosts performance metrics by up to 35% with a simple R8 update

Monzo, a UK digital bank with 15 million customers, achieved a 35% reduction in ANR rate and significant scroll performance improvements by fully enabling R8 optimizations. The key change was replacing the default `proguard-android.txt` config file with `proguard-android-optimize.txt`, removing the `-dontoptimize` instruction. They also implemented Baseline Profiles targeting scroll and rendering on their main feed, resulting in P90 scroll performance improving 71% and P95 by 87%. The post advises teams to audit Keep Rules and automate Baseline Profile generation as part of the release process.