Authentication

Login, sessions, and SSO without building it from scratch.

Authentication is one of the riskiest things to build yourself, since mistakes here directly affect account security. These tools handle login flows, session management, and SSO so you can plug in tested auth instead of hand-rolling it. Compare them on pricing at scale, which providers they support out of the box, and how much UI customization you actually need.

Auth.js

Free, self-hosted OAuth/credentials auth for Next.js and other frameworks (formerly NextAuth). Still fine for existing projects, though its own maintainers now point new projects toward Better Auth.

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Auth0

Built for enterprise auth requirements: SSO/SAML across many customer orgs, not just login for your own app.

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Better Auth

Self-hosted, framework-agnostic TypeScript auth library with no vendor lock-in. The current default recommendation for teams that want to own their auth code.

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Clerk

Drop-in auth UI plus user/org management. Probably the fastest way to ship real auth, including SSO, without building your own screens.

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WorkOS

Built specifically for B2B SaaS: SSO, SCIM provisioning, and directory sync for the enterprise deals your product will eventually need.

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