It started with a tiny flicker

I shipped a redesign, hit refresh, and caught a tiny flicker in the header.

Body text popped in system font first. Then the web font slid in behind it. The whole thing was over in maybe 90 milliseconds. But once I saw it, I could not unsee it.

That micro flash sent me down a rabbit hole that ended with a very different performance budget than the one I started with.

The crime scene: a 90ms font swap