pristine

Lens · Make it hold up

optimize

Make it feel fast on the user's real phone, then prove it.

Measures first, fixes the biggest bottleneck, and measures again. Judges speed by what people see: when content appears, whether it jumps, whether taps answer at once.

When to use it

It raises
Robustness & performance
Skip it when
Nothing is measurably slow. It never trades accessibility or quality for a number.

Try it

/pristine polish optimize the home page on mobile

Reports LCP, layout shift and interaction delay before and after.

What it changes

Typical before and after values for optimize
BeforeAfter
1.8MB hero PNG, LCP 4.1s on mobileAVIF at the rendered size with high fetch priority, LCP 1.9s
Font swap shifts the headline by 40pxMetric-matched fallback, no visible shift

Laws it applies