Astro

npm create astro@latest my-site
cd my-site
npm install
npm run dev

npx astro add tailwind        # Tailwind CSS
npx astro add react           # React component support
npx astro add mdx             # MDX support
npx astro add sitemap         # Auto sitemap.xml
npx astro add vercel          # Vercel SSR adapter

src/
  pages/          ← File-based routing (.astro, .md, .mdx)
  layouts/        ← Reusable page shells
  components/     ← UI components (.astro, .tsx, .vue, etc.)
  content/        ← Type-safe content collections (Markdown/MDX)
  styles/         ← Global CSS
public/           ← Static assets (copied as-is)
astro.config.mjs  ← Framework config

---
// src/components/Card.astro
// This block runs on the server ONLY — never in the browser
interface Props {
  title: string;
  href: string;
  description: string;
}

const { title, href, description } = Astro.props;
---

<article class="card">
  <h2><a href={href}>{title}</a></h2>
  <p>{description}</p>
</article>

<style>
  /* Scoped to this component automatically */
  .card { border: 1px solid #eee; padding: 1rem; }
</style>

src/pages/index.astro          → /
src/pages/about.astro          → /about
src/pages/blog/[slug].astro    → /blog/:slug (dynamic)
src/pages/blog/[...path].astro → /blog/* (catch-all)

---
// src/pages/blog/[slug].astro
export async function getStaticPaths() {
  const posts = await getCollection('blog');
  return posts.map(post => ({
    params: { slug: post.slug },
    props: { post },
  }));
}

const { post } = Astro.props;
const { Content } = await post.render();
---

<h1>{post.data.title}</h1>
<Content />

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

const blog = defineCollection({
  type: 'content',
  schema: z.object({
    title: z.string(),
    date: z.coerce.date(),
    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'))
  .filter(p => !p.data.draft)
  .sort((a, b) => b.data.date.valueOf() - a.data.date.valueOf());
---

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

---
import Counter from '../components/Counter.tsx';  // React component
import VideoPlayer from '../components/VideoPlayer.svelte';
---

<!-- Static HTML — no JavaScript sent to browser -->
<Counter initialCount={0} />

<!-- Hydrate immediately on page load -->
<Counter initialCount={0} client:load />

<!-- Hydrate when the component scrolls into view -->
<VideoPlayer src="/demo.mp4" client:visible />

<!-- Hydrate only when browser is idle -->
<Analytics client:idle />

<!-- Hydrate only on a specific media query -->
<MobileMenu client:media="(max-width: 768px)" />

---
// src/layouts/BaseLayout.astro
interface Props {
  title: string;
  description?: string;
}
const { title, description = 'My Astro Site' } = Astro.props;
---

<html lang="en">
  <head>
    <meta charset="utf-8" />
    <title>{title}</title>
    <meta name="description" content={description} />
  </head>
  <body>
    <nav>...</nav>
    <main>
      <slot />  <!-- page content renders here -->
    </main>
    <footer>...</footer>
  </body>
</html>

---
// src/pages/about.astro
import BaseLayout from '../layouts/BaseLayout.astro';
---

<BaseLayout title="About Us">
  <h1>About Us</h1>
  <p>Welcome to our company...</p>
</BaseLayout>

// astro.config.mjs
import { defineConfig } from 'astro/config';
import vercel from '@astrojs/vercel/serverless';

export default defineConfig({
  output: 'hybrid',  // 'static' | 'server' | 'hybrid'
  adapter: vercel(),
});

// src/pages/rss.xml.ts
import rss from '@astrojs/rss';
import { getCollection } from 'astro:content';

export async function GET(context) {
  const posts = await getCollection('blog');
  return rss({
    title: 'My Blog',
    description: 'Latest posts',
    site: context.site,
    items: posts.map(post => ({
      title: post.data.title,
      pubDate: post.data.date,
      link: `/blog/${post.slug}/`,
    })),
  });
}

// src/pages/api/subscribe.ts
import type { APIRoute } from 'astro';

export const POST: APIRoute = async ({ request }) => {
  const { email } = await request.json();

  if (!email) {
    return new Response(JSON.stringify({ error: 'Email required' }), {
      status: 400,
      headers: { 'Content-Type': 'application/json' },
    });
  }

  await addToNewsletter(email);
  return new Response(JSON.stringify({ success: true }), { status: 200 });
};

// src/components/SearchBox.tsx
import { useState } from 'react';

export default function SearchBox() {
  const [query, setQuery] = useState('');
  const [results, setResults] = useState([]);

  async function search(e: React.FormEvent) {
    e.preventDefault();
    const data = await fetch(`/api/search?q=${query}`).then(r => r.json());
    setResults(data);
  }

  return (
    <form onSubmit={search}>
      <input value={query} onChange={e => setQuery(e.target.value)} />
      <button type="submit">Search</button>
      <ul>{results.map(r => <li key={r.id}>{r.title}</li>)}</ul>
    </form>
  );
}

---
import SearchBox from '../components/SearchBox.tsx';
---
<!-- Hydrated immediately — this island is interactive -->
<SearchBox client:load />