Clerk

Clerk is a customer identity layer aimed at product teams that want polished sign-up and sign-in without building OAuth flows, session cookies, and admin dashboards from scratch. It ships prebuilt React components and APIs, a dashboard for users and organizations, and first-class patterns for B2B SaaS (organizations, roles, invitations, enterprise SSO connections). The free Hobby plan is positioned for early builds: unlimited applications, up to 50,000 monthly retained users (MRUs) per app—Clerk defines an MRU as a user who returns 24+ hours after signup—and three dashboard seats, with a fixed seven-day session lifetime on Hobby.

Paid Pro (listed around $25/month month-to-month or $20/month billed annually on clerk.com/pricing) keeps the same 50,000 included MRUs per app then charges per additional MRU on a published sliding scale, removes Clerk branding, unlocks custom session duration, MFA, satellite domains, and optional SMS sign-in (SMS is pass-through at carrier rates). Business adds SOC 2 report access, audit logs, priority support, and more dashboard seats. Separate add-ons cover enhanced B2B org limits, unlimited user impersonation for support, and Clerk Billing (listed at 0.7% of subscription volume on top of Stripe’s processing fees).

Clerk fits when frontend velocity and UX consistency matter and you are comfortable with hosted auth UIs and Clerk’s user store. Compare Auth0 or Stytch when API-first or passwordless-only positioning dominates, and Supabase Auth when your data plane is already Supabase and you want JWT + Row Level Security in one project.