Astro is a modern web framework designed for building content-driven websites that ship minimal JavaScript by default. Born from the insight that most web content is static, Astro renders HTML on the server and selectively hydrates only the interactive components that need it—an architectural pattern called Islands Architecture. Unlike traditional JavaScript frameworks that send everything to the client, Astro ships zero JavaScript unless you explicitly opt in, making it exceptionally fast for blogs, marketing sites, documentation, and e-commerce platforms. The framework's key differentiator is its multi-framework flexibility: you can mix React, Vue, Svelte, and Solid components in the same project, hydrating each island independently with precise control over when and how interactivity loads.
What This Cheat Sheet Covers
This topic spans 22 focused tables and 95 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.
Table 1: Core Rendering Modes
Astro adapts to your needs with three rendering strategies, each optimizing for different performance and deployment scenarios. Static Site Generation (SSG) pre-renders all pages at build time, delivering the fastest possible load times at the cost of rebuild overhead for content updates. Server-Side Rendering (SSR) generates HTML per request, enabling dynamic personalization and real-time data at the cost of server compute. Hybrid mode blends both approaches in a single project, letting you pre-render marketing pages while keeping user dashboards server-rendered. The key insight: Astro doesn't force an all-or-nothing choice—you control rendering per route.
| Mode | Example | Description |
|---|---|---|
output: 'static' | • Pre-renders all HTML at build time • default mode—pages are served as static files from a CDN with no server runtime required | |
output: 'server' | • Renders pages on-demand per request using a server runtime • requires an adapter (Vercel, Netlify, Node, etc.) for deployment |