Astro vs Next.js: Content Sites vs Full-Stack Apps in 2026

Astro and Next.js are both JavaScript frameworks for building production websites, but they were designed around different assumptions. Astro starts from the premise that most web content does not need JavaScript at all — so it ships none by default, hydrating only the specific components that require interactivity. Next.js starts from the premise that you are building a React application — so it ships a full React runtime and leans into the React component model for everything, from UI to data fetching to server logic.

This distinction drives every architectural decision each framework makes. Understanding it tells you which tool fits your project before you write a single line of code.

Astro vs Next.js at a Glance

Neither framework is universally better. The right choice depends on how much interactivity your project actually requires.

Architecture

Astro: Island Architecture

Astro's defining idea is the island. By default, every component you write in Astro is rendered to static HTML on the server — no JavaScript is sent to the browser. When a specific component needs to be interactive, you mark it with a client:* directive and Astro hydrates only that component, independently of the rest of the page.

---
import Header from "../components/Header.astro";
import SearchBar from "../components/SearchBar.tsx";
import ArticleBody from "../components/ArticleBody.astro";
import CommentForm from "../components/CommentForm.tsx";
---

<!-- Static HTML, zero JavaScript -->
<Header />

<!-- Static HTML, zero JavaScript -->
<ArticleBody />

<!-- Interactive island: loads React only for this component -->
<SearchBar client:load />

<!-- Interactive island: hydrates when scrolled into view -->
<CommentForm client:visible />

The result is a page that is mostly static HTML with isolated JavaScript bundles attached to specific interactive regions. Those regions — the islands — load and hydrate independently without blocking the rest of the page.

Available hydration strategies give you fine-grained control over when each island activates:

• client:load — hydrate immediately on page load
• client:idle — hydrate when the browser is idle
• client:visible — hydrate when the component enters the viewport
• client:media — hydrate when a CSS media query matches

Next.js: Full React with Server Components

Next.js runs a full React application. With the App Router, it distinguishes between Server Components (rendered on the server, zero client JS) and Client Components (rendered on server and then hydrated on the client for interactivity).

// app/blog/[slug]/page.tsx — Server Component by default
async function BlogPost({ params }: { params: { slug: string } }) {
  const post = await getPost(params.slug);

  return (
    <article>
      <h1>{post.title}</h1>
      <ArticleBody content={post.content} />
      {/* Client Component for interactivity */}
      <ShareButtons url={post.url} />
    </article>
  );
}

// components/ShareButtons.tsx
'use client';

import { useState } from 'react';

export function ShareButtons({ url }: { url: string }) {
  const [copied, setCopied] = useState(false);

  return (
    <button onClick={() => {
      navigator.clipboard.writeText(url);
      setCopied(true);
    }}>
      {copied ? 'Copied' : 'Copy link'}
    </button>
  );
}

Server Components in Next.js do not add JavaScript to the client bundle — they render to HTML on the server. But unlike Astro, the React runtime itself is always present in a Next.js app. Even a page with no Client Components still ships the React reconciler, the router, and the hydration bootstrap code.

Performance

Astro: Zero JS by Default

For content-focused pages, Astro's performance advantage is concrete. A blog post rendered with Astro ships the HTML content and whatever CSS you write. No JavaScript runtime, no hydration code, nothing to parse and execute before the page is interactive.

Lighthouse scores of 100 across all categories are achievable and common for Astro content sites without any manual optimization. The browser receives HTML, renders it, and is done. There is no "Time to Interactive" gap because there is nothing to make interactive.

The island model means JavaScript only appears when you explicitly introduce it. A documentation site with ten thousand pages and one interactive search widget sends the search widget's bundle to every page — but nothing else.

Next.js: React Runtime Overhead with Good Code Splitting

Next.js has more baseline overhead because it always ships the React runtime. For a typical Next.js app, the minimum JavaScript payload before any application code is roughly 80–120 KB (gzipped). Next.js mitigates this with aggressive code splitting, lazy loading, and the Server Components model, but the baseline cannot be eliminated.

For pages that are genuinely interactive — dashboards, authenticated views, real-time features — this overhead is negligible compared to the application code you would ship anyway. For pages where the content is the product and interactivity is minimal or absent, the overhead is unnecessary.

Next.js does provide strong tooling for performance: next/image for image optimization, automatic font optimization, bundle analyzer support, and Partial Pre-rendering (PPR) in newer releases that lets static shells be served from CDN with streaming dynamic content.

Content Management

Astro: Content Collections

Astro's built-in content collections are a first-class feature for content-heavy sites. You define a collection schema using Zod, and Astro validates all your Markdown or MDX files against it at build time. You get TypeScript types generated from your schema, runtime validation, and a query API — all without an external library.

// src/content/config.ts
import { defineCollection, z } from 'astro:content';

const blog = defineCollection({
  type: 'content',
  schema: z.object({
    title: z.string(),
    description: z.string(),
    date: z.coerce.date(),
    author: z.string(),
    tags: z.array(z.string()).default([]),
    draft: z.boolean().default(false),
  }),
});

export const collections = { blog };

---
// src/pages/blog/index.astro
import { getCollection } from 'astro:content';

const posts = await getCollection('blog', ({ data }) => {
  return !data.draft;
});

const sorted = posts.sort(
  (a, b) => b.data.date.valueOf() - a.data.date.valueOf()
);
---

<ul>
  {sorted.map((post) => (
    <li>
      <a href={`/blog/${post.slug}`}>{post.data.title}</a>
    </li>
  ))}
</ul>

If a blog post file has a missing required field or an incorrect data type, the build fails with a descriptive error. Your content schema is your contract, enforced at build time.

Next.js: MDX and Headless CMS

Next.js does not have a built-in content layer equivalent. For MDX content, the common approach uses next-mdx-remote or @next/mdx, with frontmatter parsing handled separately by gray-matter. Type safety requires manual typing of the frontmatter shape.

// lib/blog.ts
import fs from 'fs';
import path from 'path';
import matter from 'gray-matter';

export interface BlogPost {
  slug: string;
  title: string;
  date: string;
  description: string;
}

export function getAllPosts(): BlogPost[] {
  const dir = path.join(process.cwd(), 'blog');
  const files = fs.readdirSync(dir);

  return files
    .filter((f) => f.endsWith('.mdx'))
    .map((file) => {
      const raw = fs.readFileSync(path.join(dir, file), 'utf8');
      const { data } = matter(raw);
      return {
        slug: file.replace('.mdx', ''),
        title: data.title,
        date: data.date,
        description: data.description,
      };
    })
    .sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime());
}

For content-heavy applications with editors who are not developers, Next.js integrates well with headless CMS platforms such as Contentful, Sanity, and Payload. These tools provide structured editing interfaces, media management, and publishing workflows that go beyond what file-based content collections handle. If your content team needs a GUI editor rather than Markdown files, a headless CMS paired with Next.js is typically the right choice.

Multi-Framework Support

One of Astro's distinctive features is the ability to use components from multiple UI frameworks in the same project. You can have a React search bar, a Svelte animation, and a Vue form — all on the same page, each hydrated independently.

---
import ReactSearch from "../components/Search.tsx";
import SvelteSlider from "../components/Slider.svelte";
import VueDropdown from "../components/Dropdown.vue";
---

<ReactSearch client:load />
<SvelteSlider client:visible />
<VueDropdown client:idle />

In practice, most teams pick one framework and stay with it — but the option is genuinely useful when migrating from one framework to another incrementally, when adopting a third-party component from an ecosystem different from your own, or when your team has mixed expertise.

Next.js is React-only. It does not support Vue, Svelte, or other frameworks. If you are committed to React, this is not a limitation. If you want framework flexibility, Astro is the only option.

Deploying on Out Plane

Both frameworks deploy on Out Plane with the same Git-connected workflow. The differences are the adapter configuration and the port each server uses.

Astro on Out Plane

For server-side rendering, install the Node adapter and configure astro.config.mjs:

import { defineConfig } from 'astro/config';
import node from '@astrojs/node';

export default defineConfig({
  output: 'server',
  adapter: node({
    mode: 'standalone',
  }),
  server: {
    host: '0.0.0.0',
    port: 4321,
  },
});

Set the port to 4321 in your Out Plane application settings. The Node adapter with mode: "standalone" produces a dist/server/entry.mjs file that you run directly with Node:

node dist/server/entry.mjs

For fully static Astro sites (no SSR needed), use output: "static" and deploy with Buildpacks — no adapter or Dockerfile required.

For the complete setup with Dockerfile and step-by-step instructions, see the Astro deployment guide.

Next.js on Out Plane

Set output: "standalone" in next.config.ts to produce a self-contained server bundle:

import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
  output: 'standalone',
};

export default nextConfig;

Set the port to 3000 in your Out Plane application settings. The standalone build produces a server.js file that runs the full Next.js server:

node server.js

Both frameworks work with Out Plane's managed PostgreSQL and support automatic HTTPS, custom domains, environment variable management, and real-time deployment logs.

For the complete setup with Dockerfile and step-by-step instructions, see the Next.js deployment guide.

When to Choose Astro

Astro is the right choice when:

• You are building a content-focused site — blog, documentation, marketing pages, portfolio
• Page load performance is a primary concern and you want Lighthouse 100 scores without manual optimization
• Most pages have little or no client-side interactivity
• You want type-safe content management for Markdown or MDX files without an external CMS
• You want the option to use React, Vue, Svelte, or Solid components in the same project
• You are migrating a site from one framework to another and want to do it incrementally
• You want to minimize JavaScript shipped to users as a structural guarantee, not an afterthought

Astro's performance ceiling is higher for static and content-heavy pages because its zero-JS default is enforced architecturally. You cannot accidentally ship a heavy JavaScript bundle to a page that does not need it.

When to Choose Next.js

Next.js is the right choice when:

• You are building an interactive web application — dashboards, SaaS products, admin interfaces
• Your application has authenticated routes with user-specific data
• You need full-stack API routes colocated with your frontend code
• Real-time features matter — live updates, optimistic UI, websocket connections
• You are building an e-commerce application that combines static product pages with dynamic cart, checkout, and account flows
• You need Incremental Static Regeneration (ISR) to rebuild individual pages on a schedule without a full rebuild
• Your team is already invested in the React ecosystem and you want to stay within it

Next.js's rendering model is more flexible than Astro's for applications where interactivity is the product, not a feature added to content. Server Components reduce client JS compared to a pure SPA approach, but the framework is still designed around building React applications.

Summary

The difference between Astro and Next.js comes down to one question: is your project primarily about delivering content, or primarily about providing an interactive application?

Astro starts with HTML and adds JavaScript only where required. This makes it the natural choice for blogs, documentation, marketing sites, and any project where pages are mostly read rather than used. Performance is excellent by default, content management is first-class, and multi-framework flexibility is a genuine differentiator.

Next.js starts with React and optimizes the delivery of that React application through Server Components, streaming, code splitting, and ISR. It is the right choice when your product is the interface itself — dashboards, real-time tools, e-commerce flows, and authenticated applications where users interact continuously rather than read passively.

Both frameworks are production-ready, actively maintained, and deploy cleanly on Out Plane without platform-specific configuration.

Deploy either framework on Out Plane today: Astro deployment guide | Next.js deployment guide. Get started with Out Plane.