SnugugSep 27, 2025
Anyone playing with @astro 5.14 and async rendering for @sveltejs? I'm trying to do what I thought would be a basic thing, grabbing an entry from my content collection (`await getEntry(‘collection’, 'item’)`) in my script tag, but I'm getting `Cannot await outside a <svelte:boundary> with a pending snippet` as an error, and the error URL 404s.
Show threadfubitsSep 27, 2025

@snugug @astro @sveltejs can you clarify what you mean by „in my script tag“?

async Svelte in Astro works pretty well so far. I’ve tested these constellations and for islands I wrote some lines here: https://fubits.dev/notes/svelte-5-patterns-async-remote/#updates

Show threadSnugugSep 27, 2025

@fubits @astro @sveltejs I'm doing something like:

<script>
import {getEntry} from 'astro:content';

const item = await getEntry('collection', 'item');

</script>

Server render only, want to use item throughout the component. Syntax may be off, on phone.

Show threadfubitsSep 27, 2025

@snugug @astro @sveltejs just to confirm - you are doing that in a *.astro file, right?

And if yes - where is the async Svelte component being imported?

Show threadSnugug
@fubits @astro @sveltejs No, I'm doing it in a Svelte file, trying to use the new async Svelte rendering to grab the content
Sep 27, 2025 at 11:52pmWeb
Show threadSnugugSep 27, 2025
@fubits @astro @sveltejs It should be functionally identical to the included example in the 5.14 release notes (https://astro.build/blog/astro-5140/#async-rendering-support-for-svelte) and the Svelte 5 docs explicitly call out top-level `await` inside a component's <script> tag (https://svelte.dev/docs/svelte/await-expressions). I've got my `svelte.config.js` file set up correctly, but getting the error I shared (I know it's set up right because before I was getting top-level await not allowed without async rendering enabled)
Astro 5.14 | Astro

Astro 5.14 has a bumper harvest of features and DX improvements to warm the cockles of your heart, with new routing tools, async Svelte rendering, React 19 actions support, and more!

Astro
Show threadfubitsSep 28, 2025

@snugug @astro @sveltejs that’s a conceptual problem, not an async Svelte one.

Svelte is a frontend framework. Astro is a meta-framework like SvelteKit / Next / Nuxt.
Astro‘s content API belongs in Astro-land.

Frontend in Astro lives in client islands (unless wrapped in Server Islands).

You can only pass entries to Svelte (maybe even as a Promise) as props/children.

And pre-rendering would be tricky.

There’s an experimental API tho https://docs.astro.build/en/reference/container-reference/

Astro Container API (experimental)

Docs
Show threadSnugugSep 28, 2025
@fubits @astro @sveltejs Thanks for your feedback here, but, I'm not quite sure it aligns with my current problem. Even using browser built-ins with the async rendering (specifically, fetch, as demonstrated in the Astro 1.4 release notes) fails with the "cannot use `await`…" error, so there's something else going on here before being able to determine whether it's possible to use Astro content APIs in my server-only Svelte component.
Show threadfubitsSep 28, 2025

@snugug @astro @sveltejs hm, here’s a working example with async fetch and different client directives https://fubits.dev/svelte-async-server-island/

What helped me grok the relationship between Astro and async Svelte was starting with a very minimal example in StackBlitz. Maybe you could create a reproducible example of your bug.

Test: async Svelte & SSR in Astro - @fubits

Full Stack Developer specializing in Svelte, SvelteKit, Data Visualization, and Technical Project Management for NGOs and startups

fubits Portfolio
Show threadSnugugSep 28, 2025
@fubits @astro @sveltejs Thanks for the follow-up. I'd encourage you to take a look at the links I've shared—your examples are great for _some_ of the uses of async rendered Svelte, but do not actually show what I'm interested and should be possible: top-level await in a server-only component.
Show threadSnugugSep 28, 2025

@fubits @astro @sveltejs For clarity, ignore my desire to use Astro Content APIs for a moment. I'd like to get the example from the Astro 5.14 changelog working as a server-only component.

https://astro.build/blog/astro-5140/#async-rendering-support-for-svelte:~:text=contributing%20this%20feature!-,Async%20rendering%20support%20for%20Svelte,-This%20release%20adds

Astro 5.14 | Astro

Astro 5.14 has a bumper harvest of features and DX improvements to warm the cockles of your heart, with new routing tools, async Svelte rendering, React 19 actions support, and more!

Astro
Show threadfubitsSep 28, 2025

@snugug @astro @sveltejs I’m not sure if I understand by „server-only component“ but if you omit the boundary in Svelte and omit the client directive in Astro, the Svelte component will run at build time, pre-render and not hydrate on the client.

As in - the async-fetched joke example „without `svelte:boundary` + no client directive?“ further down here is static: https://fubits.dev/svelte-async-ssr/

Test: async Svelte & SSR in Astro - @fubits

Full Stack Developer specializing in Svelte, SvelteKit, Data Visualization, and Technical Project Management for NGOs and startups

fubits Portfolio
Show threadSnugugSep 28, 2025

@fubits @astro @sveltejs Ok, great, this is what I'm looking for and can't replicate (getting a svelte boundary error). I'll look at this example and see what the difference is.

And yes, I understand it won't hydrate on the client side. I personally prefer Svelte's DSL for templating to JSX that Astro uses, so I write most of my non-hydrated components with Svelte.

Show threadSnugugSep 28, 2025

@fubits @astro @sveltejs Ok, I think there must have been something wrong with the codebase I was testing in, this works as expected (even using getEntry from a Svelte component) in a clean repo. I'm curious as to how your sample app is working through; the async rendering for Astro should only be 5.14+ and yours is 5.13.10.

Either way, I've got it working now. Thanks for chatting!

Show threadfubitsSep 28, 2025
@snugug @astro @sveltejs the commit for async SSR happened in 5.13.10.
5.14 was just the announcement https://bsky.app/profile/mk.gg/post/3lzl37my5ic2u
Matt Kane (@mk.gg)

That was easy! https://github.com/withastro/astro/pull/14430

Bluesky Social
Show threadSnugugSep 28, 2025
@fubits @astro @sveltejs ah that'll explain it!