dnstrace.devRun lookup →

Site framework

Astro

Open source, the Astro Technology Company · Site framework. How DNSTrace.dev identifies it from public evidence.

Updated Sep 2026

What Astro is

Astro renders pages to HTML at build time and ships JavaScript only for the components explicitly marked as interactive, an approach it calls islands. Those islands are written into the markup as custom elements, which is what identifies the framework.

How DNSTrace.dev detects it

Detection reads the final HTTPS response and the first bytes of its markup. One matching signal is reported as strong evidence; two or more independent signals are reported as confirmed.

  • <astro-island> elements in markup — The custom element wrapping each hydrated interactive component.
  • data-astro-cid- attributes in markup — Scoped style identifiers Astro adds to component markup.
  • meta generator naming Astro — Emitted by default.

What a detection proves

The page was built by Astro.

What it does not prove

Which UI library the islands use, or where the site is hosted. An Astro page with no interactive components may carry only the generator tag.

Common questions

Why do some Astro pages show no island markup?

A page with no hydrated components ships no islands. In that case the scoped style attributes or the generator tag are the remaining evidence.

Can Astro pages contain React or Vue?

Yes. Astro islands can be written in several UI libraries, and DNSTrace.dev reports those separately only when their own markers appear.

Compare with

Site frameworkGatsby

Open source, maintained under Netlify

Application frameworkSvelteKit

Open source, Svelte project

Application frameworkNext.js

Open source, maintained by Vercel

Frontend application platformNetlify

Netlify, Inc.

Check a domain

Run a full lookup to see the delivery layer, the detected application stack, live TLS and the announcing network side by side.

Inspect the live response See the delivery platform

Run a lookup →Application stack →Evidence model →