Keycloak vs Auth0
Compare self-managed Keycloak and Auth0 for application identity, supported integrations, extensibility, maintenance and the complete operating cost.
Which identity approach fits the brief?
Consider Keycloak when its identity server and supported protocols fit the application and the team can operate it or procure a clearly scoped service. Consider Auth0 when a managed platform and its selected package fit the same application journey. Compare a running service on both sides. Free project software does not include the hosting, database, updates and recovery needed to maintain an identity deployment.
Seven differences that change the shortlist
| Buying question | Keycloak | Auth0 |
|---|---|---|
| Product boundary | Open-source identity server; managed distributions are separate offers | Managed application identity platform under a selected package |
| Protocol integration | OpenID Connect, OAuth 2.0 and SAML support | Validate the required supported connection and application integration |
| Existing identities | User federation and identity brokering under the chosen configuration | Identity connections and migration scope under the chosen package |
| Customisation | Themes, configuration and custom extensions require maintenance | Supported extensibility and customisation have package and platform boundaries |
| Operations | Assign infrastructure, database, availability, updates and recovery | Vendor service plus customer-owned app, configuration and integration work |
| Free boundary | Free project software; hosting and support separate | Limited Free plan; advanced and B2B/B2C scope differ |
| Full cost | Infrastructure, support, operators, extensions and integration | Package, users, connections, machines, add-ons and integration |
Four worked buying briefs
These are hypothetical scenarios with explicit assumptions. They do not establish equal capabilities, measured usability or a negotiated price.
| Requirement | Proposed exercise | Accept when |
|---|---|---|
| App integration | Complete the same supported test login journey | Required claims and app behaviour reconcile |
| Identity connection | Connect an authorised isolated source | Identifiers, mapping and account ownership are explicit |
| Change control | Review and reverse a permitted configuration change | A second owner can restore the known journey |
| Operating plan | Walk through a written service interruption scenario | Recovery, support and customer responsibilities are identified |
A required application
Can the actual app complete its supported sign-in flow?
Keycloak: Use the retained Keycloak version, client and protocol configuration.
Auth0: Use the retained Auth0 package, connection and SDK configuration.
Check the app’s expected identifiers, claims and error handling.
An existing directory
Can an isolated identity source connect as required?
Keycloak: Validate the intended federation or brokering configuration.
Auth0: Validate the intended connection or migration configuration.
Record attribute ownership and any existing account-linking assumptions.
A maintained change
Can another owner review and reverse a login-related change?
Keycloak: Use the proposed configuration, theme or extension release process.
Auth0: Use the supported configuration or extensibility release process.
Keep a known test journey and explicit rollback responsibility.
A service interruption
What is the supported recovery and escalation path?
Keycloak: Review the deployment, database backup and restoration plan.
Auth0: Review the retained service scope and customer-owned recovery steps.
A backup file or a status page alone does not prove application recovery.
Compare a running service, not a download
Keycloak supplies project software and guides. A retained deployment still needs an operating arrangement: database, infrastructure, access, monitoring, updates, backup verification and recovery. A commercial managed distribution is a separate contract.
Auth0 manages its platform, while the application team still owns integration, configuration, user mapping and application authorisation. List these responsibilities explicitly on both proposals.
Standards support is a starting point
Supported protocols make integration possible, but applications can depend on particular claims, sessions, extensions and recovery behaviour. Inventory those requirements before assuming an existing client migrates unchanged.
Test one complete application journey and a maintained change. Price custom code and its upgrade work alongside the service or infrastructure estimate rather than treating extensibility as costless.
Questions before you choose
Is Keycloak a free hosted identity service?
The project is free software. Hosting, operations, commercial distributions and support are separate purchases or internal responsibilities.
Does protocol support guarantee a complete migration?
No. Validate the actual clients, claims, user mapping, sessions, extensions and recovery requirements.
Which has lower total cost?
That depends on the retained platform and required operating work. This comparison provides a matched costing brief without claiming universal savings.
Your practical evaluation pack
Download the identity evaluation checklist (CSV)
Four proposed checks with blank evidence and owner fields. Keep the actual audience, application, package and operating arrangement with the evaluation.
Turn the comparison into your own evaluation
Use the same criteria and priorities for both products, keep unknowns unassessed and record the plan and evidence behind your ratings.
Build a Keycloak vs Auth0 scorecard →Keep the assumptions with the figures
Use the date, billing cycle, units and limits with each example. Check current account terms before purchasing. Unverified prices and model costs stay unpriced.
Download the buying examples as JSON ↓Share the comparison
Use these examples when discussing the shortlist with your team.