TL;DR
Supabase Auth integrates directly with your Postgres database and Row Level Security policies. Clerk is a dedicated auth service with more features but requires syncing user data. Supabase wins for database-integrated security and data ownership; Clerk wins for auth features and developer experience. Choose based on whether you're building on Supabase or need dedicated auth features.
Supabase Auth and Clerk take different approaches to authentication. Supabase includes auth as part of their database platform with tight RLS integration. Clerk is a dedicated authentication service focused solely on identity. Understanding these architectural differences helps you choose the right solution.
Security Feature Comparison
| Feature | Supabase Auth | Clerk |
|---|---|---|
| RLS Integration | Native, seamless | Requires sync |
| User Data Location | Your database | Clerk's servers |
| MFA | TOTP, Phone | TOTP, SMS, Passkeys |
| User Management UI | Basic dashboard | Full-featured |
| Bot Protection | CAPTCHA integration | Built-in |
| Social Providers | 20+ providers | 20+ providers |
| Enterprise SSO | SAML (enterprise) | SAML, OIDC |
| SOC 2 | Type II | Type II |
Database Integration
Supabase RLS Integration
Supabase Auth's killer feature is native Row Level Security integration. Auth users are automatically available in RLS policies through auth.uid(). This enables security policies directly in the database without additional API layers. Authorization happens at the data layer.
Clerk Data Syncing
Clerk manages users on their infrastructure. To use Clerk users in database queries, you need to sync user IDs or data via webhooks. This adds complexity but keeps auth separate from your database. You can still implement RLS, but it requires webhook setup.
Choose Supabase Auth When: You're building on Supabase and want integrated RLS-based authorization. Supabase Auth shines when auth and database security work together. Best for applications where Row Level Security is central to your authorization model and you want user data in your database.
Choose Clerk When: You need advanced auth features like comprehensive user management, better MFA options, or passkeys. Clerk's dedicated focus on auth provides a better developer experience for complex auth needs. Best when auth is a priority and you don't need tight RLS integration.
Data Ownership
Supabase: Your Data
Supabase stores auth users in your Postgres database. You have full access to user data, can query it directly, and control its lifecycle. This is valuable for data sovereignty and simplifies querying user-related data.
Clerk: Their Data
Clerk stores user data on their infrastructure. You access it via API or sync it to your database. For applications with strict data residency requirements, this third-party storage may be a concern.
Best Practices
- For Supabase: Always enable RLS on tables with user data
- For Supabase: Use service role keys only server-side
- For Clerk: Set up webhook syncing for database queries
- For both: Enable MFA for sensitive applications
- For both: Validate sessions server-side
Can I use Clerk with Supabase?
Yes, you can use Clerk for auth while using Supabase as your database. You'll sync Clerk user IDs to Supabase and use them in RLS policies. This gives you Clerk's auth features with Supabase's database, but adds webhook complexity.
Is Supabase Auth less secure than dedicated providers?
No, Supabase Auth uses industry-standard security practices and is SOC 2 Type II certified. The integration with RLS actually provides stronger data-layer security. Clerk has more auth-specific features, but security isn't compromised with Supabase.
Validate Your Authentication
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