Clerk
A hosted user-management and authentication service.
Prebuilt sign-in components, organisations, MFA and session management; you pay per active user.
Backend & APIs
What is the difference among Clerk, Auth.js and Better Auth?
Clerk is a hosted authentication service with ready-made UI; Auth.js and Better Auth are open-source libraries you run in your own app, with Better Auth offering a broader built-in feature set.
- Technologies
- 3
- Difference questions
- 50
What each one is
Auth.js
An open-source authentication library (formerly NextAuth.js).
OAuth providers, email and credentials with adapters for your database; you own the data and UI.
Better Auth
A framework-agnostic TypeScript authentication library.
Email and password, OAuth, two-factor, organisations and plugins, running in your own app and database.
At a glance
| Aspect | Clerk | Auth.js | Better Auth |
|---|---|---|---|
| Hosting | Hosted service | Your app | Your app |
| UI | Prebuilt components | Build your own | Build your own |
| Data ownership | Clerk | You | You |
| Cost | Per user | Free | Free |
| Best for | Fastest, full-featured setup | Next.js OAuth sign-in | Self-hosted, feature-rich auth |
The 10 most-asked difference questions
Subjective questions 10
1What is the main difference among Clerk, Auth.js and Better Auth?Asked almost every time
Clerk is a hosted authentication and user-management service with ready-made UI, where Clerk stores users and sessions. Auth.js and Better Auth are open-source libraries that run inside your own app and store users in your own database, with Better Auth offering a broader built-in feature set through plugins.
2Who owns the user data in each?Asked almost every time
With Clerk, user records and sessions live in Clerk's service, synced to your app by webhooks or APIs. With Auth.js and Better Auth, users, accounts and sessions live in your database through adapters.
3When would you choose Clerk?Asked almost every time
When you want production-ready sign-in, sign-up, profile, organisations and multi-factor auth in hours, with prebuilt components and managed security, and per-user pricing is acceptable.
4When would you choose Auth.js?Asked almost every time
When you need OAuth sign-in with providers such as Google or GitHub in a Next.js app, want to own the data and pay nothing, and are happy to build your own UI.
5When would you choose Better Auth?Asked almost every time
When you want a self-hosted, TypeScript-first library with email and password, OAuth, two-factor, passkeys, organisations and admin features out of the box, owning the data in your database.
6How does UI differ?Very often asked
Clerk provides drop-in components such as SignIn, UserButton and OrganizationSwitcher. Auth.js and Better Auth give you APIs and helpers; you build or adopt UI components yourself.
7How do sessions work?Very often asked
Clerk manages short-lived session tokens and refresh automatically. Auth.js supports JWT or database sessions. Better Auth uses database-backed sessions with cookie caching options.
8How does cost compare?Very often asked
Clerk has a free tier then charges by monthly active users and features. Auth.js and Better Auth are free libraries; you pay only for your database and hosting.
9How do they integrate with Next.js?Very often asked
Clerk offers middleware or proxy helpers, server helpers like auth() and client components. Auth.js has a Next.js integration with route handlers and auth(). Better Auth mounts a handler route and offers server and client helpers.
10How does multi-factor authentication compare?Very often asked
Clerk includes MFA with SMS, authenticator apps and backup codes. Better Auth provides two-factor through a plugin. Auth.js needs custom work or additional libraries for MFA.
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