Promises Not Resolving After Upgrading SvelteKit Packages

[singhjaskaran0501]

Describe the bug

After upgrading the SvelteKit dependencies, API calls made to backend servers no longer resolve their promises when the page is reloaded. The issue does not occur when the user navigates between pages — in that case, the promises resolve correctly and data loads as expected.

This behavior appeared after updating to the newer versions of SvelteKit packages.

Temporary Workaround
Downgrading the following packages restores normal behavior:

"@sveltejs/adapter-node": "5.3.1",
"@sveltejs/kit": "2.36.3"

After reverting to these versions, the promises resolve correctly in all cases.

Expected Behavior
API calls should behave consistently between page reloads and client-side navigation. Promises should resolve correctly in both cases.

Reproduction

1. Upgrade to the latest versions of @sveltejs/kit and @sveltejs/adapter-node
2. Implement an API call inside a load function that fetches data from a backend server
3. Reload the page directly
4. Observe that the promise for the API call never resolves
5. Navigate between pages using client-side routing — observe that it works normally.

Example

+posts.server.ts

export const load: PageLoad = async ({ fetch, depends }) => {
  return {
    posts: fetch(url('/posts?_limit=5'))
  };
};

+page.svelte

<script lang="ts">
  export let data: {
    posts: Promise<any>;
  };
</script>

{#await data.posts}
Loading....
{:then posts}
  <ul>
    {#each posts as post}
      <li>
        <h3>{post.title}</h3>
        <p>{post.body}</p>
      </li>
    {/each}
  </ul>
{/await}

System Info

System:
  OS: macOS
  Node: v22.18.0
  npm: 10.9.3

Packages:
  @sveltejs/kit: [latest version] (❌ causes issue)
  @sveltejs/adapter-node: [latest version] (❌ causes issue)
  svelte: 5.x
  vite: 6.x

Adapter:
  Node adapter (using `adapter-node`)

Environment:
  Mode: development

Severity

blocking an upgrade

Additional Information

This issue seems related to how SvelteKit handles SSR or the load lifecycle during full-page reloads in recent versions. There might be a regression or change in async handling on the server side.

[PatrickG]

It seems like it works.
Can you provide a minimal reproduction?

[ihr-it-projekt]

Hi, @singhjaskaran0501 is my colleague. You need to run this as an builded application with node adapter. In Dev Mode all went fine.

[PatrickG]

@ihr-it-projekt I already tried that and it worked.
Does your issue only happen when a load function throws an error() and the page doesn't load at all? Then this is probably the same as #14684.
Otherwise we need a reproduction.

[ihr-it-projekt]

We are working on intensive testing. Will give you feedback soon

[firatciftci]

I have a similar issue I had opened a bug report for that have remained unanswered at #14496. Could it be the same problem?

[PatrickG]

@singhjaskaran0501 @ihr-it-projekt is this issue fixed by updating sveltekit to 2.47.2?

[singhjaskaran0501]

@PatrickG

I created a new project from scratch. I am using the mentioned combo of the versions and working fine for me.

@sveltejs/kit: "2.46.5"
@sveltejs/adapter-node": "5.3.3"

Tried updating the packages on my existing project and then will revert if something would come up!

[singhjaskaran0501]

@PatrickG
Tried with this specific version, This also worked..
@sveltejs/kit: 2.47.2