Keycloak vs ZITADEL
Both are alternatives to Auth0. Here's how they stack up — verified facts, no spin.
Also searched as ZITADEL vs Keycloak — same comparison, one verdict.
Both are authentication & identity tools with the same broad shape, but Keycloak scores 90 against ZITADEL's 82 on data ownership and exit cost — the gap is in how easily you could leave.
Keycloak
TOP PICKThe mature, CNCF-backed open-source identity and access management server.
Keycloak is a full-featured IAM server originally built by Red Bull's security team and now a CNCF Incubating project. It supports OIDC, OAuth2, and SAML, social and enterprise identity brokering, fine-grained authorization, and a built-in admin console, and it's the most widely deployed self-hosted alternative to Auth0/Okta in production today.
ZITADEL
A cloud-native, API-first identity platform with a generous self-hosted core.
ZITADEL is a modern identity and access management platform built API-first for cloud-native and multi-tenant SaaS use cases. It supports OIDC, SAML, passkeys/WebAuthn, and fine-grained actions/hooks for customizing the auth flow in code, and offers both a managed cloud and a self-hostable core.
Side by side
10 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| Keycloak | ZITADEL | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 90 | 82 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first data | Yes | Yes |
| License | Apache-2.0 | AGPL-3.0 |
| Pricing | Free / self-host (Docker image or standalone distribution); commercial support available via Red Hat build of Keycloak (RHBK) for enterprises that want a support contract. | Free / self-host under AGPL-3.0; ZITADEL Cloud offers a managed free tier plus paid usage-based plans for teams that don't want to run the server themselves. |
| RAM to run it wellThe figure that actually matters, not the vendor's minimum. | 4 GB | 4 GB |
| Realistic running costWhat the box costs each month if you run it yourself. | $24–40/mo plus a database, against Okta or Auth0 per-user pricing that becomes brutal above the free tier | $24–40/mo plus Postgres, against Okta or Auth0 per-user pricing |
| Setup timeHonest first-install estimate, not the marketing quickstart. | A day to stand up, a week to configure realms and flows correctly | Half a day |
| Ongoing maintenanceThe part nobody budgets for. | Moderate to high. It is enterprise software with an enterprise upgrade cadence and its own vocabulary. | Moderate. |
Keycloak is Macrostack's recommended Auth0 alternative, so it's our pick here.
Weighing both against staying on Auth0? Is Auth0 free? What it actually costs →
Keycloak
Strengths
- +Apache-2.0, fully open-source, no feature gating between a 'community' and 'enterprise' edition
- +Extremely mature — 10+ years in production at large scale, CNCF Incubating project with active governance
- +Broad protocol support (OIDC, SAML, OAuth2) and identity brokering to external IdPs out of the box
- +Large ecosystem of themes, extensions, and Kubernetes operators for production deployment
Trade-offs
- −Runs on the JVM — heavier resource footprint than lightweight Go-based alternatives, and the admin console/config model has a real learning curve
- −You own uptime, patching, and database backups for something security-critical — a genuine operational responsibility Auth0 absorbs for you
- −Theming the login UI to match a product's brand takes more custom work than Auth0's Universal Login customization
ZITADEL
Strengths
- +Strong native support for passkeys/WebAuthn and modern passwordless flows out of the box
- +API-first design and 'Actions' hooks make custom auth logic (e.g. custom claims, external calls during login) straightforward without forking the codebase
- +Built for multi-tenancy (organizations/projects) from the ground up, closer to Auth0's B2B model than most self-hosted options
- +Active development with frequent releases and a responsive open-source community
Trade-offs
- −AGPL-3.0 requires that any modified version offered as a network service also be released under AGPL — a real legal consideration for SaaS companies embedding it
- −Younger project than Keycloak with a smaller track record at very large scale
- −Some advanced features are positioned toward the paid ZITADEL Cloud tier rather than the self-hosted core
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose Keycloak
if a lower exit cost matters more to you than any single feature, and apache-2.0, fully open-source, no feature gating between a 'community' and 'enterprise' edition.
Choose ZITADEL
if strong native support for passkeys/WebAuthn and modern passwordless flows out of the box.
Neither, yet
if both carry a real cost you should weigh first — runs on the JVM — heavier resource footprint than lightweight Go-based alternatives, and the admin console/config model has a real learning curve, and aGPL-3.0 requires that any modified version offered as a network service also be released under AGPL — a real legal consideration for SaaS companies embedding it. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
What it takes to run these yourself
Real requirements and honest running costs, not the vendor quickstart.
Self-hosting Keycloak
4 GB RAM · A day to stand up, a week to configure realms and flows correctly
$24–40/mo plus a database, against Okta or Auth0 per-user pricing that becomes brutal above the free tier
Self-hosting ZITADEL
4 GB RAM · Half a day
$24–40/mo plus Postgres, against Okta or Auth0 per-user pricing
Keycloak vs ZITADEL — common questions
Is Keycloak a better fit than ZITADEL for authentication & identity?
It depends on what you are optimising for, and the honest split is this: Keycloak scores 90 to ZITADEL's 82 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. ZITADEL earns its place on a different axis — strong native support for passkeys/WebAuthn and modern passwordless flows out of the box. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
Keycloak keeps its data local or in open formats, so leaving is an export rather than a negotiation. ZITADEL is still self-hostable, so the files stay on your server either way — but it is not local-first by design, so check what its export produces before you rely on it.
Can I self-host Keycloak or ZITADEL?
Both can be self-hosted. The difference is what it costs you in time rather than whether it is possible — see the setup and maintenance rows above.
Are Keycloak and ZITADEL both alternatives to Auth0?
Yes — both appear in our Auth0 comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off Auth0 and now choosing between the two replacements, which is a narrower and much easier question.
Related alternative guides
Facts verified 2026-07-14. Licenses and pricing change — spotted something out of date? That's a correction we want.