Keycloak vs Auth0

Self-host swap-in for Auth0. · Self-host Auth0 · Keycloak on os-alt

Keycloak is one of the open-source self-host replacements for Auth0 — license Apache-2.0, 20-30min docker-compose (Keycloak + Postgres) to stand up, and $10 vps for a small team; $20+ for production with ha postgres. Compare against Auth0's $240/mo at 1k MAU on B2C Essentials; jumps fast at scale below.

	Keycloakopen-source	Auth0paid SaaS
Category	Identity / SSO / authentication-as-a-service	Identity / SSO / authentication-as-a-service
License / pricing	`Apache-2.0`	$240/mo at 1k MAU on B2C Essentials; jumps fast at scale
Starting price	$0 self-host	$25/user/mo
GitHub	keycloak/keycloak ★ 34.4k · last commit todayalive	closed source
Setup time	20-30min docker-compose (Keycloak + Postgres)	SaaS — sign up + bill
Monthly cost	$10 VPS for a small team; $20+ for production with HA Postgres.	from $25/user/mo ($240/mo at 1k MAU on B2C Essentials; jumps fast at scale)

Switching from Auth0 to Keycloak

Auth0 → Tenant → Export users (JSON, including hashed passwords if on bcrypt). Keycloak → Admin Console → realm-import via JSON or the Keycloak `kcadm.sh` CLI. Bcrypt hashes import directly — users keep their passwords. Map Auth0 Rules / Actions to Keycloak event listeners or authentication-flow scripts.

Good fit for: B2B apps that want SAML + OIDC + LDAP federation in one server, and don't mind Java footprint.
Weak at: Java-heavy; theming and UX out of the box are dated vs Auth0.

Other open-source self-host alternatives to Auth0

Authentik
MIT15min docker-compose$10 VPS — Python + Postgres + Redis stack.
Zitadel
Apache-2.020min docker-compose$10-15 VPS — Go binary + CockroachDB or Postgres.

In a terminal? npx os-alt auth0 prints Auth0's self-host options — how the CLI works →

FAQ

Is Keycloak a free alternative to Auth0?

Yes — Keycloak is open source under Apache-2.0. Self-host cost: $10 VPS for a small team; $20+ for production with HA Postgres.. Auth0 starts at $25/user/mo ($240/mo at 1k MAU on B2C Essentials; jumps fast at scale).

How long does Keycloak take to set up vs Auth0?

Self-hosting Keycloak: 20-30min docker-compose (Keycloak + Postgres). Auth0 is a hosted SaaS — sign up and you're in.

What is Keycloak good at, and what is it weak at?

Good fit for: B2B apps that want SAML + OIDC + LDAP federation in one server, and don't mind Java footprint.. Weak at: Java-heavy; theming and UX out of the box are dated vs Auth0..