How We Cut Chat UI Frame Time by 8% with One Jetpack Compose Optimization

We optimized our chat UI performance by replacing SubcomposeLayout with standard Layout for dynamic timestamp positioning. Key results: 8% reduction in P99 frame times, fewer frame drops, and cleaner code.

Introduction

Smooth scrolling is critical for chat apps - lag or stutter can severely impact user satisfaction and retention. Chat interfaces face unique challenges due to dynamic, high-density content like text bubbles, images, emojis, and timestamps.

Our team recently encountered a subtle but challenging requirement while working on our chat implementation: dynamically positioning timestamps inline with the last line of text when space permits, or dropping them to a new line when the text is too wide. This seemingly minor design decision uncovered significant performance bottlenecks.

In this article, I'll walk you through two approaches that we used - SubcomposeLayout and the optimized Layout alternative - to demonstrate how seemingly small implementation choices can dramatically impact ...