sveltekit-remote-functions

name	sveltekit-remote-functions
description	SvelteKit remote functions guidance. Use for query(), form(), command(), and prerender() patterns in .remote.ts files.

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