My experience building Sonner, a toast library.
The short version
How Sonner was built and why it won an already crowded market, beginning with the name. It now runs to tens of millions of downloads a week.
Our summary, not the author’s text. The essay itself stays where they published it.
Goes well with
emil-design-eng
The design-engineering house style behind Sonner and Vaul.
Emil's main skill. Mostly animation, with the UI-polish and component judgement that surrounds it: what to build, how far to push it, and when to stop.
npx skills add https://github.com/emilkowalski/skills
animate
Builds an animation from scratch, decisions in the order that matters.
Should it animate at all, what purpose, which tool, which properties, which curve and duration, how it interrupts, how it exits. Then writes the implementation.
npx skills add https://github.com/emilkowalski/skills --skill animate
review-animations
Reviews your motion strictly, against Emil's rules.
A production-critical pass over animation quality, timing and consistency in a diff. Pairs with improve-animations, which does the same for a whole codebase.
npx skills add https://github.com/emilkowalski/skills --skill review-animations