Preact in context of Astro and also in general
Last updated on 7 Feb 2026 Summary Preact is a lightweight, React-compatible UI library that implements the React API with a much smaller runtime. React ≈ feature-rich, heavy Preact ≈ minimal, fast, React-shaped Astro + Preact architecture Astro itself is not a SPA framework . Astro renders HTML at build time Interactive UI pieces are islands Each island can be: Preact, React, Vue, Svelte, Solid, etc. Preact is often the best default choice when: You want React-like syntax You want minimal client JS Why Preact matters specifically in Astro Astro’s core philosophy is: Ship zero JavaScript by default. Hydrate only where needed. Preact fits this philosophy extremely well because: Tiny runtime (~3–4 KB gzipped) Fast hydration Same mental model as React Excellent for islands architecture Astro uses Preact as: A first-class UI framework A lighter alternative to React for interactive components Preact vs React ...