What is Astro and why does it feel so fast?

Astro is a web framework built for content-first websites: marketing sites, blogs, documentation and business sites that mainly present content. The core idea is simple: a page is assembled into HTML ahead of time, and JavaScript only reaches the browser where it is genuinely needed. That single principle makes an Astro site fast by default, without you having to optimise after the fact. In this article you will read what Astro is, how it works, who it is for and how to get started.

What exactly is Astro?

Astro is an open source framework for building websites. Where many modern frameworks assemble every page in the browser with a full JavaScript application, Astro reverses that logic: it delivers ready-made HTML and keeps JavaScript to a minimum. You build with components in .astro files, which look a lot like HTML but have the power of a framework (props, layouts, loops).

The result is a site that loads fast, is easy to maintain and scores well on discoverability. Astro is used by brands such as Unilever, Visa and NBC News (Cloudflare).

How does Astro work?

Astro turns your pages into HTML during a build step (or on the server). The heavy lifting, fetching content, applying styling, composing components, therefore happens before the visitor requests the page. As a result the visitor gets readable HTML immediately, not a blank screen that first has to run JavaScript.

For the parts that do need interaction, Astro uses the islands architecture. An interactive piece, such as a search bar or a carousel, becomes an island with its own JavaScript. The rest of the page stays static HTML. How that works exactly, you can read in the islands architecture explained.

Why does an Astro site feel so fast?

The speed does not come from a trick, but from a default: send nothing unless it is needed. With a classic single-page app, the browser first has to download, parse and run an entire application before the page is usable. With Astro the page is HTML straight away, and only the islands load their JavaScript.

Less JavaScript means a faster render (LCP), a smoother response to interaction (INP) and less work for the visitor’s device, especially on an average phone. Why those metrics matter for SEO, you can read in Core Web Vitals and SEO.

Which sites is Astro made for?

Astro excels at content-first sites:

• marketing and business sites;
• blogs and news sites;
• documentation and knowledge bases;
• landing pages and portfolios.

For highly interactive applications with a lot of real-time client-side state (think of a complex dashboard app or an online editor), frameworks that run entirely on the client are often a better fit. Astro is honest about that boundary: it is built for sites where content takes centre stage, and there it is exceptionally strong.

Which languages and frameworks can you use?

Astro does not force a framework choice. You write most pages in .astro, and for the interactive islands you can add React, Svelte, Vue, Solid or other frameworks, even side by side in the same project. Astro only loads the runtime of such a framework where you place an island. That way you pay the cost of a framework only where you actually use it.

How do you manage content in Astro?

You manage content with Content Collections. You define a schema (which fields a blog post has, which are required, what type they have), and Astro checks that structure during the build. A missing title or a wrong date format is spotted before the site goes live, not after. If you want editors to work in a familiar environment, you connect a headless CMS as the content source.

Astro compared to other approaches

	Astro	Classic SPA (e.g. React)	WordPress
JavaScript by default	Little to none	A lot	Often a lot (plugins)
Best for	Content sites	Interactive apps	Self-managed content
Rendering	HTML ahead of time, islands where needed	Everything in the browser	PHP per visit
Content management	Files or headless CMS	Your choice	Built-in editor

A detailed comparison with WordPress can be found in Astro vs WordPress; the comparison with Next.js is covered separately.

Is Astro free, and who makes it?

Astro is free and open source under the MIT licence. Since January 2026 the team behind Astro has been part of Cloudflare, but the framework stays free, open source and multi-platform: you can run an Astro site on various hosting providers, not just on Cloudflare. The most recent major version, Astro 7, was released on 22 June 2026 with speed as its theme; read about it in what is new in Astro 7.

How do you get started with Astro?

You need a basic knowledge of the web (HTML, CSS and some JavaScript), but for anyone who already builds sites the learning curve is gentle. You set up a new project with the official starter command, choose a template or start empty, and the documentation guides you through the first pages, layouts and collections. From there you build on as you would build a regular website, but with the speed thrown in for free.

Conclusion

Astro is a web framework that makes content sites fast by making it normal to ship little JavaScript. You get static HTML where you can, interaction where you must, and type-safe content management on top. For marketing sites, blogs and documentation that is a particularly strong combination. This site, AstroBuild, is itself built with it; see why Astro is fast by design or follow the release calendar to watch live how Astro evolves.