Svelte 5: `$props()` can only be used at the top level of components

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

<script>
  // Correct: one top level declaration, defaults and rest included
  let { title, count = 0, ...rest } = $props();

  // Fails: inside a function
  function setup() { const { title } = $props(); }

  // Fails: conditionally
  if (browser) { let { title } = $props(); }
</script>

<!-- Reading a prop that the parent never passes is a separate warning -->
<!-- Declare it with a default rather than reaching for $$props -->

# Runes only apply in runes mode: a component still in legacy mode
# reports different errors for the same code
npx sv check --threshold error

How to diagnose Svelte errors

Svelte errors mostly arise at the compiler's boundaries: the $ store prefix only works on real stores in component context, and SvelteKit's load functions run in two different environments with different capabilities. A 500 from a load function usually means server-only code (a database client, a secret, fs) reached a universal load that also runs in the browser.

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

1. Check whether the file is a universal load (+page.js) or a server-only load (+page.server.js). Anything touching secrets or the filesystem belongs in the latter.
2. Read the full server-side stack trace in the terminal, not just the browser's 500 page: SvelteKit hides details in production for security.
3. For $ prefix errors, confirm the value is an actual store with a subscribe method and that you are inside a component, not a plain module.
4. Use $env/static/private and $env/dynamic/private for secrets so the compiler enforces the server-only boundary for you.
5. Reproduce with vite build && vite preview; dev-mode behaviour differs meaningfully from the production build.

Tools worth reaching for

• vite build && vite preview
• SvelteKit terminal logs
• svelte-check
• $env/static/private

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

📖 svelte.dev

Related Svelte errors

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• Svelte: '$' prefix can only be used with storesThe $ auto-subscription was used on a value that is not a store (no subscribe method), or a…
• SvelteKit: 500 error in load functionA load function threw, returned a non-serialisable value, or accessed browser-only APIs…
• SvelteKit: Cannot prerender pages with actionsPrerendering happens at build time and produces a static file, while a form action needs a…

See all 10 Svelte errors →

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This entry is maintained by hand. If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.