Clerk

Clerk is a complete user management and authentication platform that gives you production-ready auth in minutes, not weeks. It provides beautiful, pre-built UI components for sign-in, sign-up, user profile management, and organization management that you can drop into your React, Next.js, Remix, or Expo application. Behind the polished components is a robust auth backend supporting email/password, magic links, social OAuth (Google, GitHub, Apple, and 20+ providers), multi-factor authentication, SAML SSO, and passkeys. Clerk handles the entire user lifecycle: registration, email verification, session management, JWT tokens, and user metadata. For multi-tenant SaaS apps, Clerk Organizations lets users create teams, invite members, manage roles and permissions. The API provides webhooks for user events, user impersonation for support teams, bot protection, and device tracking. Clerk integrates with popular frameworks through official SDKs and provides middleware for protecting routes and API endpoints. The dashboard includes user search, activity logs, and customization options for branding. Compared to Auth0 or Firebase Auth, Clerk stands out with its modern UI components, developer experience, and transparent pricing starting with a generous free tier of 10,000 monthly active users.