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Astro vs Next.js: Which Should You Use for Your Site?

Astro ships almost no JavaScript by default and shines for content sites. Next.js is a full React application framework. How they differ in philosophy, performance, data handling and hosting — and a simple rule for picking between them.

Astro and Next.js both build websites, both can render pages on the server, and both are popular with AI coding tools. But they start from opposite assumptions:

  • Astro assumes your site is mostly content — and ships as little JavaScript as possible.
  • Next.js assumes your site is an application — built with React from top to bottom.

The core difference: islands vs full React

In Astro, pages are rendered to plain HTML. By default, zero JavaScript goes to the browser. When you need interactivity — a search box, a carousel — you add a component as an island, and only that piece loads JavaScript:

---
import Header from '../components/Header.astro'
import SearchBox from '../components/SearchBox.jsx'
---
<Header />
<article>...</article>
<SearchBox client:visible />   <!-- only this ships JS, when scrolled into view -->

Astro islands can be React, Vue, Svelte or Solid — even mixed.

In Next.js, everything is React. With the App Router, Server Components render on the server and send no JavaScript for themselves, but the page still runs inside React's runtime, and any interactive ("use client") component brings React along with it. (What is Next.js?, React Server Components explained)

Side by side

Astro Next.js
Best for Blogs, docs, marketing, portfolios Dashboards, SaaS, logged-in apps
JavaScript by default None React runtime
UI framework Any (or none) React only
Content (Markdown/MDX) Built-in content collections Possible, more setup
Server rendering Yes (with an adapter) Yes
API routes / backend Yes, endpoints Yes, route handlers + server actions
Learning curve Gentle Steeper (server vs client components, caching)
Hosting Static anywhere, or Node/edge adapters Node anywhere; most features first on Vercel

Performance

For content sites, Astro is fast with almost no effort, because there's simply less to download. Good Core Web Vitals come almost free.

Next.js can be just as fast, but it takes more care: keeping components on the server, avoiding large client bundles, getting caching right.

For an app with lots of interactivity, the difference shrinks — you need the JavaScript either way, and Next.js's structure for data and state helps.

When to choose Astro

  • Your site is mainly pages people read.
  • SEO and load speed are the priority.
  • You want Markdown/MDX content with type-checked frontmatter.
  • You want to use different UI frameworks, or none.

When to choose Next.js

  • Your site is mainly things people do — log in, edit, manage, buy.
  • Lots of shared state and interactive UI.
  • You're already all-in on React and its ecosystem.
  • You want server actions, middleware and auth patterns in one framework.

Can you use both?

Yes — a common setup is an Astro marketing site and blog at yourapp.com and a Next.js (or Vite React) app at app.yourapp.com. Each tool does what it's best at. (Subdomain vs subdirectory)

What about AI tools?

Most AI app builders default to React (Next.js or Vite). Claude Code and similar agents handle Astro well too — it's well documented and simple. If you're building a content site, it's worth asking for Astro explicitly.

The summary

  • Astro: content-first, zero JS by default, islands for interactivity.
  • Next.js: app-first, React everywhere, more power and more complexity.
  • Reading → Astro. Doing → Next.js. Both → use both.

EasySpawn runs Astro, Next.js or both side by side on one server with your own domains and automatic SSL — and Claude Code can work on either. See how it works or join the waitlist.

Related: What Is Next.js? · Static vs Dynamic Websites · What Is a Framework? · React vs Vue vs Svelte

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