Astro is a modern web framework that pioneered the 'islands architecture' — shipping zero JavaScript by default and hydrating only the interactive components that need it, resulting in extremely fast initial page loads. Unlike traditional React or Vue frameworks, Astro components compile to pure HTML at build time, and interactive widgets (React, Vue, Svelte, or Solid components) are loaded as isolated islands when needed. It's the framework of choice for documentation sites, blogs, marketing pages, and any content-focused site where performance is paramount. Astro sites are identifiable through the astro-island custom element wrapping client-side interactive components, assets served from the _astro/ directory path with content-hash filenames, and the astro-island attribute in the DOM. The framework produces minimal JavaScript payloads, which makes Astro sites score exceptionally high on Core Web Vitals.
Paste any URL to instantly detect whether it was built with Astro. Our engine checks 6 technical signals.
Astro is used across many industries. These are the most common website types built on this platform:
Businesses of all sizes
Fast, reliable site building with professional results
Designers and developers
Powerful tools with minimal setup
Startups
Quick launch with scalable infrastructure
Content creators
Beautiful presentation for your work
Every Astro website leaves distinctive technical fingerprints. Here's what to look for:
JavaScript Patterns
2 script patterns linked to Astro
HTML Attributes
3 HTML patterns in the page source
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