Performance is a user feature

The situation

A patient-facing application had slow initial experiences that affected usability and retention. The goal was not simply to make a benchmark green; it was to make important screens feel meaningfully faster.

How I approached it

I traced the critical rendering path and used measurements to find work that delayed useful content.

• Measured before changing code and kept a repeatable baseline
• Reduced unnecessary component work and expensive rendering paths
• Prioritized changes users would actually perceive
• Released incrementally and compared the result

Result and lesson

Focused refactoring reduced load time by roughly 40%. The lasting lesson was that performance work needs a user-centered target, a measurement, and verification after release.

What I would watch next

Bundle growth, slow-device behavior, long tasks, real-user percentiles, and regressions introduced by later features.