Astro vs Next.js: When to Use Which

Originally published at pkgpulse.com Astro ships zero JavaScript to the browser by default. Every page is static HTML unless you explicitly opt in to client-side interactivity. Next.js ships a JavaScript runtime on every page — even static ones — because it assumes your app needs hydration, routing, and React on the client. That single architectural decision drives every trade-off between these two frameworks: build speed, page load performance, Core Web Vitals, framework flexibility, and full-stack capability. We compared them using real data from PkgPulse . Here's what the numbers say — and when each choice is the right one. At a Glance Metric Astro Next.js Default JS Shipped 0 KB 80-120 KB+ (React runtime) Page Load (static content) ~40% faster than Next.js Baseline JS Payload (comparable pages) ~90% less than Next.js Baseline Build Time (1,000-page docs site) ~18 seconds ~52 seconds Core Web Vitals Near-perfect consistently 80-85 Lighthouse (static export) Framework Support React,