SvelteKit Quickstart

1. Installation

The Svelte Clerk SDK gives you access to prebuilt components, runes, and helpers to make user authentication easier.

npm install svelte-clerk

2. Set your Clerk API keys

Add your Clerk Publishable Key to your .env file. This key can always be retrieved from the API Keys page in the Clerk Dashboard.

PUBLIC_CLERK_PUBLISHABLE_KEY=pk_test_xxxxxxxx
CLERK_SECRET_KEY=sk_test_xxxxxxx

3. Configure server handler

This handler will authenticate requests and gives you access to the Auth object via event.locals.auth() inside your server loaders and actions.

// hooks.server.ts
import { withClerkHandler } from 'svelte-clerk/server';

export const handle = withClerkHandler();

4. Add locals types

Inside your src/ directory, update the app.d.ts file to ensure that the locals added by the Clerk handler are properly typed.

/// <reference types="svelte-clerk/env" />

declare global {
	namespace App {...}
}

5. Add <ClerkProvider> to your root layout

All Clerk runes and components must be children of the <ClerkProvider> component, which provides active session and user context.

<script lang="ts">
	import type { Snippet } from 'svelte';
	import { ClerkProvider } from 'svelte-clerk';

	const { children }: { children: Snippet } = $props();
</script>

<ClerkProvider>
	{@render children()}
</ClerkProvider>

To enable SSR support, pass the initial auth state to the return object of the load function.

// src/routes/+layout.server.ts
import { buildClerkProps } from 'svelte-clerk/server';
import type { LayoutServerLoad } from './$types';

export const load: LayoutServerLoad = ({ locals }) => {
	return {
		...buildClerkProps(locals.auth())
	};
};

6. Protect your pages

Client-side

To protect your pages on the client-side, you can use Clerk's <Show> control component to control visibility based on the user's authentication state.

<script lang="ts">
	import { Show, SignInButton, UserButton } from 'svelte-clerk';
</script>

<template>
	<header>
		<Show when="signed-out">
			<SignInButton />
		</Show>
		<Show when="signed-in">
			<UserButton />
		</Show>
	</header>
</template>

Server-side

To protect your routes, you can use the load function to check for the userId singleton. If it doesn't exist, redirect your user back to the sign-in page.

import { redirect } from '@sveltejs/kit';

export const load = async ({ locals }) => {
	const { userId } = locals.auth();

	if (!userId) {
		return redirect(307, '/sign-in');
	}

	return {
		userId
	};
};

7. Create your first user

Run your project with the following command:

npm run dev