Nanostores
~250-byte state library — framework-agnostic, works with React, Vue, Svelte, Solid, Lit. Default state solution for Astro projects.
Andrei Sitnik (PostCSS, Storeon, Logux). Atomic stores: $counter = atom(0). Adapter per framework. Good for micro-frontends where different parts use different frameworks but share state. Competitors: Zustand (mostly React-only), Jotai (mostly React-only), Pinia (Vue), Svelte stores.