Start with Identity

At a glance

Auth0 is the breadth choice — every protocol, every social provider, every compliance certification. Clerk is the modern UX choice — pre-built React components, slick UI, fast time-to-value.

When Auth0 wins

You need protocol breadth (SAML, OIDC, WS-Federation, LDAP) for legacy SaaS app integration
Enterprise customers expect a recognized brand on your security page
Multi-tenant B2B with sophisticated organization patterns
You need flexibility in self-hosted or sovereign cloud deployment

When Clerk wins

Next.js, React, or Remix application as the primary stack
You want polished UI components, not auth primitives
Time-to-first-login matters more than long-tail flexibility
Per-MAU economics work for your user volume (under ~500K MAU sweet spot)

Pricing reality

Clerk publishes pricing and is generous in free tier. Auth0 lists pricing but enterprise negotiation is where real numbers land. Above 1M MAU, both vendors require negotiation; Auth0 has more enterprise muscle.

Migration between them

Clerk-to-Auth0 is harder than Auth0-to-Clerk because Clerk users come with rich component history. Either direction requires password migration via either bcrypt rehash or forced reset.

Verdict