SvelteKit Guide Best Authentication for SvelteKit (2026)
Compare the best authentication solutions for SvelteKit. We review Lucia, Auth.js, Clerk, and more with hooks integration and server-side session handling.
SvelteKit's server hooks and load functions make authentication elegant when done right. You can protect routes, check sessions, and handle auth flows all server-side. The framework's simplicity means auth libraries need to match—no complex abstractions needed.
Pourquoi C'est Important
SvelteKit is server-first like Remix, meaning auth runs primarily on the server. This is more secure than client-heavy approaches. But you need a library that works with SvelteKit's hooks system and doesn't fight the framework's conventions.
Considérations Clés
Hooks Integration
SvelteKit's handle hook is where auth middleware lives. Your library should integrate cleanly here, setting locals.user for downstream use in load functions.
Session Strategy
Lucia uses database sessions (more secure, requires DB). Auth.js supports JWT (stateless, edge-compatible) or database. Managed services handle this for you.
Type Safety
SvelteKit has great TypeScript support. Your auth library should provide typed session data through app.d.ts declarations, not require type assertions.
Self-Hosted vs Managed
Lucia is self-hosted and lightweight. Auth.js is self-hosted with more features. Clerk is managed with the best DX but vendor lock-in.
OAuth Complexity
Social login (Google, GitHub) adds complexity. Managed services handle OAuth flows. Self-hosted libraries require more configuration but give more control.
Nos Recommandations
Auth.js
Meilleur Global Excellent Support SDK OfficielAuth.js (formerly NextAuth) has first-class SvelteKit support via @auth/sveltekit. Handles OAuth, email/password, database sessions. Self-hosted and open source. The most feature-complete self-hosted option.
npm install @auth/sveltekit 
Clerk
Meilleur Géré Bon Support SDK OfficielClerk's SvelteKit SDK provides the same great DX as their other framework integrations. Pre-built components, user management, MFA out of the box. 10k MAU free. Best if you want auth done in minutes, not hours.
npm install @clerk/sveltekit 
Supabase Auth
Meilleur avec Supabase Bon Support SDK OfficielIf you're using Supabase as your database, their auth integrates tightly. SSR helpers work with SvelteKit load functions. Row-level security ties auth to data access. Unlimited users on free tier.
npm install @supabase/supabase-js @supabase/ssr 
Kinde
Meilleur Plan Gratuit Bon Support SDK OfficielKinde offers 10,500 MAU free with good SvelteKit support. Growing alternative to Clerk with competitive pricing. Worth considering if cost is a concern.
npm install @kinde-oss/kinde-auth-sveltekit 
Auth0
Meilleur pour Entreprises Bon SupportAuth0 doesn't have an official SvelteKit SDK, but community solutions work well. Best for enterprise apps needing SAML, LDAP, and advanced security features. Use Auth.js with Auth0 provider for easier integration.
npm install @auth/sveltekit @auth/auth0-provider Comparaison Rapide
| Service | TypeScript | Edge | Offre Gratuite | Temps de Configuration |
|---|---|---|---|---|
| Auth.js | full | ✓ | Unlimited (self-hosted) | 20 min |
| Clerk | full | ✓ | 10k MAU | 10 min |
| Supabase Auth | full | ✓ | 50k MAU | 15 min |
| Kinde | full | ✓ | 10.5k MAU | 15 min |
Démarrage Rapide
import { SvelteKitAuth } from '@auth/sveltekit';
import GitHub from '@auth/sveltekit/providers/github';
export const { handle, signIn, signOut } = SvelteKitAuth({
providers: [GitHub],
callbacks: {
async session({ session, token }) {
if (token.sub) session.user.id = token.sub;
return session;
},
},
});
// In +page.server.ts for protected routes:
import { redirect } from '@sveltejs/kit';
export async function load({ locals }) {
const session = await locals.auth();
if (!session) throw redirect(303, '/auth/signin');
return { user: session.user };
}Modèles d'Intégration Courants
Auth.js + Prisma + PostgreSQL
Self-hosted auth with Auth.js, Prisma adapter for database sessions, PostgreSQL for data. Full control, no vendor lock-in.
Clerk + Supabase
Clerk for auth with great UX, Supabase for database. Webhook syncs Clerk users to Supabase. Best of managed auth with open database.
Supabase Full Stack
Supabase for auth, database, and storage. Single provider, row-level security, realtime subscriptions. Simplest full-stack SvelteKit setup.