Auth.js vs Clerk
Auth.js and Clerk both answer the same question: how do users sign in? The long-running open source auth layer formerly called NextAuth, mostly a thin wrapper around OAuth providers. Drop-in hosted auth with prebuilt sign-in components, so you ship login on day one instead of building it. The real split is ownership: Auth.js runs inside your project and leaves the operational work with you, while Clerk runs the hard parts as a service and takes a dependency in exchange.
Verdict
The real split is ownership: Auth.js runs inside your project and leaves the operational work with you, while Clerk runs the hard parts as a service and takes a dependency in exchange.
Pick Auth.js if
- ✓Enormous library of OAuth providers configured with a few lines each.
- ✓Years of production usage mean most errors already have a forum answer.
- ✓Adapters let you keep sessions in whichever database you already chose.
Pick Clerk if
- ✓Prebuilt sign-in, sign-up and profile components mean almost no UI work.
- ✓Organizations, invitations and roles are built in rather than bolted on later.
- ✓Middleware helpers make protecting Next.js routes close to a one-liner.
| Comparison | Auth.js | Clerk |
|---|---|---|
| Pricing shape | Free and open source. Costs are whatever your identity providers and database charge. | Free tier for small user counts, then usage-based per monthly active user, with add-ons for organizations and advanced factors. |
| Frameworks | Next.js, SvelteKit | Next.js, Nuxt, React Native, Expo |
| In one line | The long-running open source auth layer formerly called NextAuth, mostly a thin wrapper around OAuth providers. | Drop-in hosted auth with prebuilt sign-in components, so you ship login on day one instead of building it. |
Pricing described qualitatively because published plans change often. Checked 2026-08-23. Confirm current terms on Auth.js and Clerk.
Auth.js
Strengths
- ✓Enormous library of OAuth providers configured with a few lines each.
- ✓Years of production usage mean most errors already have a forum answer.
- ✓Adapters let you keep sessions in whichever database you already chose.
- ✓Stateless JWT sessions work without any session store at all.
Tradeoffs
- ✗Anything past OAuth, like invitations or roles, you design yourself.
- ✗Callback and adapter APIs have churned across major versions more than once.
- ✗Documentation lags the code, so reading the source becomes routine.
- ✗Debugging silent callback failures is a known rite of passage.
Clerk
Strengths
- ✓Prebuilt sign-in, sign-up and profile components mean almost no UI work.
- ✓Organizations, invitations and roles are built in rather than bolted on later.
- ✓Middleware helpers make protecting Next.js routes close to a one-liner.
- ✓Session management, device tracking and MFA are handled without custom code.
Tradeoffs
- ✗Users live in Clerk, so joining auth data to your own tables needs syncing.
- ✗The prebuilt components fight you once your design diverges from theirs.
- ✗Per-active-user pricing scales with growth even when auth stays trivial.
- ✗Migrating off means exporting users and rebuilding sessions from scratch.
Same pair, different context
Frequently asked questions
Is Auth.js or Clerk better?
Neither is better in the abstract. The real split is ownership: Auth.js runs inside your project and leaves the operational work with you, while Clerk runs the hard parts as a service and takes a dependency in exchange. The wrong choice here is usually recoverable, so weight speed of decision over certainty.
What is the main drawback of Auth.js?
Anything past OAuth, like invitations or roles, you design yourself. Callback and adapter APIs have churned across major versions more than once.
What is the main drawback of Clerk?
Users live in Clerk, so joining auth data to your own tables needs syncing. The prebuilt components fight you once your design diverges from theirs.
Can you switch from one to the other later?
Usually, at a cost that grows with how much of your product leans on the authentication layer. Keep the integration behind a thin module of your own and the migration stays a weekend rather than a quarter.