Keycloak vs Auth0

Auth0 and Keycloak are both developer identity / ciam solutions. Auth0 developer-first identity platform for customer authentication and CIAM, while Keycloak open-source IAM platform with SSO, identity brokering, and fine-grained authorization. The best choice depends on your organization's size, technical requirements, and budget.

Choose Auth0 if best developer experience in the identity industry with comprehensive SDKs is your priority and development teams building customer-facing applications that need flexible, API-first authentication with extensive SDK support and customizable login experiences. Choose Keycloak if completely free — no licensing costs regardless of user count matters most and organizations with engineering expertise that want full control over their identity platform, avoid vendor lock-in, and eliminate IAM licensing costs.

Auth0 starts at Free up to 25,000 MAUs; B2C paid from $35/mo; B2B paid from $150/mo (per monthly active user (mau)). Keycloak starts at Free (open source) / Red Hat Build of Keycloak via subscription (open source + enterprise subscription). As always, the sticker price only tells part of the story. Factor in add-ons, implementation costs, and what's actually included at each tier.

It depends on how deeply Keycloak is embedded in your stack. Most teams run both in parallel for a few weeks before cutting over. Check whether Auth0 supports importing your existing configs or policies. That's usually the biggest time sink.