Clerk

Clerk brand colours

Extracted from the artwork and ranked by how much of the mark each covers — not from a brand book, so treat them as observed rather than official.

Clerk is authentication delivered as pre-built React components rather than a redirect to a hosted login page, which is the single design decision the whole product follows from. Sign-in, sign-up, user profile, organisation switcher and invitation flows ship as drop-in UI with matching hooks and middleware for Next.js, Remix, Astro and React Router, plus organisations, roles and permissions for B2B applications. That gets a real product to a working multi-tenant auth flow in an afternoon. The costs are a heavier client-side footprint than a token-verification library, pricing that scales with monthly active users, and a component model that is pleasant until you need a login flow it did not anticipate. It competes with Auth0 and Stytch as hosted services, WorkOS on enterprise SSO specifically, Supabase and Firebase where auth comes bundled, and Better Auth and Lucia for teams who want the logic in their own codebase.