Astro vs SvelteKit: which should you choose?
Both ship remarkably little JavaScript, but they aim at different jobs. Astro is built for content-driven sites that should ship almost no JS by default; SvelteKit is the full application framework for Svelte, compiling components down to tiny bundles. Here's the honest split — and why the framework you pick doesn't have to dictate how you build and ship it.
Pick by what you're actually building:
- Content-driven site (blog, docs, marketing) → Astro — zero-JS islands, MDX & content collections.
- Interactive site or app, all-in on Svelte → SvelteKit — compile-away tiny bundles, load fns, form actions.
- Mostly content with a little Svelte → Astro with Svelte islands — you may not need SvelteKit.
- Build & deploy either, on any host → Buddy — own the build, choose the host.
The honest split
Where each one wins
Choose Astro when…
- The site is content-first: blog, docs, marketing, a portfolio or a content-heavy storefront.
- You want zero client JavaScript by default and only hydrate the interactive islands you mark.
- You like mixing UI frameworks — Svelte, React, Vue, Solid — or plain
.astrocomponents. - You want MDX and content collections with strong content tooling out of the box.
Choose SvelteKit when…
- You're building an interactive site or application and you're all-in on Svelte.
- You want Svelte's compiler to compile most framework code away — tiny bundles, no virtual DOM.
- You need full app features: load functions, form actions, endpoints, nested layouts.
- Excellent developer experience across SSR, SSG and SPA/CSR in one framework matters.
Side by side
Astro vs SvelteKit, compared
Both are free and open-source (MIT). The difference is philosophy: HTML-first content framework with optional islands vs a full Svelte application framework.
| Dimension | Astro | SvelteKit |
|---|---|---|
| UI / language | Any (Svelte/React/Vue/.astro) | Svelte / JS·TS |
| Primary use case | Content-driven sites | Interactive sites & apps |
| Rendering | SSG · SSR · Server Islands | SSR · SSG · SPA |
| Client JS by default | Zero (islands) | Compiles most away |
| App features | Content-focused | Load fns, form actions, endpoints |
| Ecosystem & content tooling | Strong content tooling | Smaller, app-focused |
| Learning curve | Gentle | Gentle |
| License | MIT | MIT |
| Best for | Blogs, docs, marketing | Interactive apps, tiny bundles |
Compiled July 2026 from each project's official docs.
Where Buddy fits
Own the build, choose the host
Buddy is one way to do this — GitHub Actions, GitLab CI and Bitbucket Pipelines can build these frameworks too. The point is that your build and host stay a choice you own, independent of the framework.
The Astro-vs-SvelteKit decision is about the framework. How you build and where you deploy is a separate choice — and one you shouldn't have to redo if you change your mind. Buddy builds either framework and ships it anywhere.
Builds both
A Node.js build step compiles either an Astro or a SvelteKit project — same pipeline model, no lock-in to one framework.
Deploy anywhere
Ship to Cloudflare, Netlify, Vercel, your own CDN/VPS, or Buddy's Dev Cloud (MicroVM + static hosting).
Preview env per PR
Every branch or pull request gets a real URL so changes get reviewed on a live deploy before merge.
Free to start
Free tier at €0/mo, then Pro €29/mo and Hyper €99/mo as concurrency and team size grow.
Common questions
Astro vs SvelteKit — common questions
Should I use Astro or SvelteKit?
Use Astro for content-driven sites — blogs, docs, marketing — where you want zero JavaScript by default, MDX and content collections, and the freedom to mix UI frameworks. Use SvelteKit when you're building an interactive site or application and you're all-in on Svelte: its compiler compiles most framework code away for tiny bundles, and it gives you full app features like load functions, form actions and endpoints. Astro can host Svelte islands, so if you only need a little Svelte on a content site you may not need SvelteKit at all.
Which ships less JavaScript, Astro or SvelteKit?
Both are light, but in different ways. Astro ships zero JavaScript by default for content and only hydrates the islands you mark, so for mostly-static content it tends to send the least JS. SvelteKit uses Svelte's compiler to turn components into minimal, virtual-DOM-free JavaScript, which is very small for interactive UIs. For a mostly-static content page Astro usually wins; for an interactive app SvelteKit's compiled output is the more efficient way to ship that interactivity.
Can I use Svelte with Astro instead of SvelteKit?
Yes. Astro supports Svelte components as hydrated islands via the @astrojs/svelte integration. If your site is content-first and you only need Svelte in a few interactive spots, Astro lets you drop Svelte in as islands while keeping the rest of the page as zero-JS HTML — so you may not need SvelteKit. Reach for SvelteKit when you want Svelte across a whole interactive app plus its routing, load functions and form actions.
How hard is it to migrate between Astro and SvelteKit?
Svelte components themselves port cleanly between the two. The real work is the app layer: re-expressing SvelteKit's routing, load functions, form actions and endpoints as Astro pages, islands and content collections (or vice versa). Markdown/MDX content is portable in both directions. A content-heavy site moves fairly quickly; an interactive app with lots of load/form logic takes longer because that logic has to be rebuilt in the other framework's conventions.