Clerk ranks #2 in Authentication & Identity AI search.

Clerk is a San Francisco-based authentication and user management platform founded in 2019, targeting developers building modern web and mobile applications. The platform provides drop-in UI components—including pre-built sign-in, sign-up, user profile, and organization management screens—paired with flexible REST APIs and SDKs across 20+ frameworks including Next.js, React, Expo, and Go. Beyond user-facing flows, Clerk covers B2B multi-tenancy with organization management, role-based access control, SAML/OIDC enterprise SSO, machine-to-machine authentication, MCP-based AI agent identity, and subscription billing via Stripe. The product is SOC 2 Type 2 and CCPA compliant, with built-in bot detection and fraud prevention. Backed by $134M from investors including Andreessen Horowitz, CRV, Stripe, Menlo Ventures, and Anthropic's Anthology Fund, Clerk reports managing over 200 million users across more than 15,000 applications.