API Building Blocks
Clerk Backend API
An identity and user management API for users, sessions, organizations, invitations, tokens, machine authentication, API keys, and application authentication workflows.
Clerk provides authentication, user management, session handling, organizations (multi-tenancy), and enterprise identity features through APIs, SDKs, and prebuilt UI components. It supports popular frameworks like Next.js, React, Expo, and more, allowing developers to implement secure authentication without building it from scratch.
Features
- Email, phone, and username authentication
- Social login (Google, GitHub, Apple, etc.)
- Passwordless authentication (magic links, OTPs, passkeys)
- Multi-factor authentication (MFA)
- Enterprise SSO (SAML & OIDC)
- User and session management
- Organizations and multi-tenancy
- Webhooks and backend APIs
- Prebuilt authentication components
- SDKs for Next.js, React, Expo, Node.js and other frameworks
Common Use Cases
- SaaS authentication
- B2B applications with organizations and roles
- Consumer apps with social login
- Next.js and React applications
- Enterprise identity integration
- Passwordless authentication