The Sacred Secret Behind Our App's Speed

A handful of people used our app in ways we never planned for, and pushed it into corners we had never looked at. Chasing those unlikely edge cases turned up optimisations that made the app faster for everyone, not just for the few who found them.

This talk is about that: how unexpected usage drives efficiency gains, why the weird bug report is often the most valuable one, and what the sacred secret behind our app’s speed turned out to be. Given with Matteo Rattotti at Pragma Conference 2025.