Keycloak and WSO2 Identity Server are both mature open-source identity platforms that provide single sign-on with OpenID Connect, OAuth 2.0 and SAML 2.0, plus multi-factor authentication and directory integration. Keycloak often suits teams that want a lightweight, container-friendly identity server with a large community, while WSO2 Identity Server often suits organizations that want wider legacy protocol support, scripted adaptive authentication and a vendor support subscription.
Both are good choices. Your users, protocols, team skills and support needs should decide, not a feature checklist alone. This article compares the two in plain terms and ends with six questions to guide the choice.
The short answer
| Topic | Keycloak | WSO2 Identity Server |
|---|---|---|
| Often best for | Teams that want a lightweight, container-friendly identity server | Organizations that want wider legacy protocol support and a vendor support subscription |
| Strengths | Large community, realms, identity brokering, user federation with LDAP and Active Directory | Scripted adaptive authentication, multi-tenancy, enterprise identity federation |
| Watch-outs | Custom login logic beyond the built-in options usually means writing Java extensions | Check the current terms for updates and support before you plan production use |
| Support model | Community, or commercial support through the Red Hat build of Keycloak | Community, or a vendor support subscription from WSO2 |
Keycloak in brief
Keycloak is an open-source identity and access management server. Commercial support is available through the Red Hat build of Keycloak.
- Runtime: built on Quarkus, runs well in containers and has a Kubernetes Operator.
- Structure: realms separate users, clients and settings, so one server can host several isolated identity domains.
- Directories and federation: user federation with LDAP and Active Directory, and identity brokering with social and enterprise identity providers.
- Authentication: multi-factor authentication, WebAuthn and passkeys, and X.509 client certificate login.
- Customization: themes for login pages, and Java extension points called Service Provider Interfaces (SPIs) for custom logic.
- Authorization: built-in authorization services for fine-grained policies.
WSO2 Identity Server in brief
WSO2 Identity Server is an open-source identity server developed by WSO2, with vendor support available through a subscription.
- Standards: OpenID Connect, OAuth 2.0 and SAML 2.0 for single sign-on and API security.
- Adaptive authentication: conditional login flows written as scripts, for example to ask for a second factor only for certain users or situations.
- Multi-tenancy and B2B: tenants and organization management for serving several customers or partners from one deployment.
- User stores: connections to LDAP, Active Directory and database user stores.
- Authentication: multi-factor authentication, identity federation and X.509 certificate login.
Side-by-side comparison
| Area | Keycloak | WSO2 Identity Server |
|---|---|---|
| Open source | Yes | Yes |
| Single sign-on standards | OpenID Connect, OAuth 2.0, SAML 2.0 | OpenID Connect, OAuth 2.0, SAML 2.0 |
| Multi-factor authentication | Yes, including WebAuthn and passkeys | Yes, including adaptive, script-based rules |
| X.509 certificate login | Yes | Yes |
| Directory integration | LDAP and Active Directory user federation | LDAP, Active Directory and database user stores |
| Separating customers or teams | Realms | Tenants and organizations |
| Custom login logic | Java SPIs and themes | Adaptive authentication scripts |
| Commercial support | Red Hat build of Keycloak | WSO2 subscription |
Both products release new versions often. Check each row against the official documentation for the version you plan to run.
How to choose: six questions
- Who are your users? Employees, customers and partners have different needs for self-registration, branding and scale.
- Do you need older protocols? If some applications still use WS-Federation or WS-Trust, confirm support in each product’s current documentation before you decide.
- Do you need true multi-tenancy? Serving many separate customers from one deployment is a different design problem from separating a few internal teams.
- What skills does your team have? Java, Kubernetes and scripting skills all affect how easily you can extend and run each platform.
- Community or vendor contract? Decide whether community support is enough, or whether you need a support contract with agreed response times.
- How much custom login logic do you need? Decide where that logic should live: in scripts, in Java extensions or in your applications.
Run a short proof of concept
A comparison table only gets you so far. Before you commit, run your preferred platform, or both, against a few real applications for a few weeks. Test the things that are hard to change later:
- your main login flows, including MFA enrollment and account recovery;
- federation with at least one partner or external identity provider;
- the connection to your real directory, with realistic numbers of users and groups;
- admin roles and delegation, so help desk staff can do their job without full admin rights;
- upgrades, backup and restore, and sending logs to your SIEM;
- performance under the login peaks you expect, such as the start of the working day.
Write down what you had to customize on each platform. That list is a good guide to how much effort each one will take to run.
Migration tips
Whether you move between the two platforms or from a commercial identity provider, the same points come up:
- Users and passwords: check whether your password hash format can be imported. If it cannot, migrate users at their next login.
- Applications: re-register OIDC clients and SAML service providers, and plan for changes to redirect URIs and metadata.
- MFA: some users may need to enroll passkeys and authenticator apps again.
- Cut-over: run both systems side by side for a period and move applications in waves.
Where PKI fits in IAM
Both platforms can accept X.509 client certificates for login. Certificates on smart cards, managed laptops or devices give strong, phishing-resistant authentication for users and machines.
Those certificates have to come from a certificate authority and be renewed and revoked on time. Our guide to private CA vs public CA explains which certificates you should issue yourself, and DictaLabs offers PKI and certificate-based authentication design, including certificate-based integration with IAM platforms.
If you plan to use Keycloak with a signing platform, our earlier post on configuring Keycloak as an external identity provider for remote signing walks through a basic setup.
How DictaLabs helps
DictaLabs works with both WSO2 Identity Server and Keycloak. According to the Keycloak and WSO2 identity and access management services page, the services cover:
- identity architecture and strategy;
- SSO and federation across applications, including cross-organization (B2B) federation;
- passwordless authentication with passkeys (FIDO2 / WebAuthn), certificate-based authentication, and adaptive MFA;
- OAuth 2.0, OpenID Connect, SAML 2.0, and LDAP and Active Directory integration;
- role-based and attribute-based access control;
- custom IAM development, managed IAM operations, version upgrades and migrations, and integration with PKI, CLM and digital signature platforms.
Next step
If you are choosing between Keycloak and WSO2 Identity Server, or planning a migration, contact our identity experts to talk through your identity architecture, users and protocols before you commit.
