Ory Kratos vs ZITADEL
Both are alternatives to Auth0. Here's how they stack up — verified facts, no spin.
Also searched as ZITADEL vs Ory Kratos — same comparison, one verdict.
Ory Kratos and ZITADEL are closely matched on ownership (84 vs 82) — this one comes down to pricing and to which trade-offs below you can live with.
Ory Kratos
A headless, API-only identity server for teams that want to build their own login UI.
Ory Kratos is a headless identity and user-management server — it handles registration, login, MFA, account recovery, and profile management entirely through APIs, with no bundled UI. It's designed for teams who want full control over the login experience and are comfortable building their own frontend against a well-documented identity API.
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.
| Ory Kratos | ZITADEL | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 84 | 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 under Apache-2.0; Ory Network offers a managed hosted version with a free tier and paid usage-based plans for teams that prefer not to operate it themselves. | 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. | 1–2 GB for Kratos, PostgreSQL and a login UI together. Kratos itself is a single Go binary and keeps no state of its own. | 4 GB |
| Realistic running costWhat the box costs each month if you run it yourself. | $6–12/mo for a small app's login service on a 1–2 GB VPS, plus an SMTP provider for verification and recovery emails | $24–40/mo plus Postgres, against Okta or Auth0 per-user pricing |
| Setup timeHonest first-install estimate, not the marketing quickstart. | An hour for the quickstart; days to a week for production, because you build or adapt the login UI and write the identity schema | Half a day |
| Ongoing maintenanceThe part nobody budgets for. | Back up, read the changelog for breaking changes and run `kratos migrate sql` on every upgrade. Open-source releases have come about twice a year (v25.4.0 in November 2025, v26.2.0 in March 2026), and your UI has to keep up with SDK changes. | Moderate. |
Ory Kratos edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
Weighing both against staying on Auth0? Is Auth0 free? What it actually costs →
Ory Kratos
Strengths
- +Clean Apache-2.0 license with no enterprise-only carve-out directory, unlike several peers
- +Headless-by-design means zero UI lock-in — build exactly the login experience your product needs
- +Pairs well with companion Ory projects (Hydra for OAuth2/OIDC server, Keto for permissions) for teams that need the full stack
- +Strong documentation and a security-first design philosophy from the Ory team
Trade-offs
- −Headless-only means you must build and maintain your own login/registration UI — meaningfully more upfront engineering work than Auth0's Universal Login or authentik's flow builder
- −Running the full picture (Kratos + Hydra + Keto) for OAuth2/OIDC server capability adds operational complexity beyond a single service
- −Smaller ecosystem of ready-made UI kits/themes compared to Keycloak or authentik
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 Ory Kratos
if a lower exit cost matters more to you than any single feature, and clean Apache-2.0 license with no enterprise-only carve-out directory, unlike several peers.
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 — headless-only means you must build and maintain your own login/registration UI — meaningfully more upfront engineering work than Auth0's Universal Login or authentik's flow builder, 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 Ory Kratos
1–2 GB for Kratos, PostgreSQL and a login UI together. Kratos itself is a single Go binary and keeps no state of its own. RAM · An hour for the quickstart; days to a week for production, because you build or adapt the login UI and write the identity schema
$6–12/mo for a small app's login service on a 1–2 GB VPS, plus an SMTP provider for verification and recovery emails
Self-hosting ZITADEL
4 GB RAM · Half a day
$24–40/mo plus Postgres, against Okta or Auth0 per-user pricing
Ory Kratos vs ZITADEL — common questions
Is Ory Kratos a better fit than ZITADEL for authentication & identity?
It depends on what you are optimising for, and the honest split is this: Ory Kratos scores 84 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?
Ory Kratos 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 Ory Kratos 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 Ory Kratos 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.
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Facts verified 2026-07-14. Licenses and pricing change — spotted something out of date? That's a correction we want.