SvelteKit Remote Functions

Current Status

Remote functions are experimental in SvelteKit 2.58. Enable them in svelte.config.js :

export default { kit: { experimental: { remoteFunctions: true } }, compilerOptions: { experimental: { async: true } } // only for await in components };

Quick Start

File naming: export remote functions from *.remote.ts or *.remote.js . Remote files can live anywhere under src except src/lib/server .

Which function?

• Dynamic reads → query()

• Progressive forms → form()

• Event-handler mutations → command()

• Build-time/static reads → prerender()

Example

// posts.remote.ts import { command, query, requested } from '$app/server'; import * as v from 'valibot';

export const getPosts = query(v.object({ tag: v.optional(v.string()) }), async (filter) => { return db.posts.find(filter); });

export const createPost = command(v.object({ title: v.string() }), async (data) => { await db.posts.create(data);

for (const { query } of requested(getPosts, 5)) {
	void query.refresh();
}

});

Client:

<script lang="ts"> import { createPost, getPosts } from './posts.remote';

const posts = $derived(await getPosts({ tag: 'svelte' }));

</script>

<button onclick={() => createPost({ title: 'New' }).updates(getPosts)}> Create </button>

Current Rules

• Remote functions always run on the server, even when called from the browser.

• Args/returns use devalue ; avoid functions, class instances, symbols, circular refs, and RegExp .

• Validate exposed inputs with Standard Schema (valibot , zod , arktype , etc.) or use .unchecked /'unchecked' deliberately.

• query.batch() batches calls from the same macrotask to solve n+1 reads.

• form().enhance() submit() returns true when submission is valid/successful and false for validation failures.

• .updates() is client-requested; server handlers must opt in with requested(queryFn, limit) .

• requested() now yields { arg, query } ; call query.refresh() /query.set(...) on the bound instance.

• limit is required for requested() to cap client-controlled refresh requests.

• Inside command/form handlers, use void query.refresh() /void query.set(value) ; SvelteKit awaits and serializes the updates.

• Prefer form() over command() where progressive enhancement matters.

• Use prerender() for data that changes at most once per deployment.

• Last verified: SvelteKit 2.58.0, 2026-04-24

Reference Files

• references/remote-functions.md - Current patterns, examples, and gotchas