Enterprise SSO: Keycloak or Microsoft Entra ID? How to choose

Written by Davide Ferraretto

When a B2B/B2C system needs to integrate with the digital identity already used within a company, the question isn't whether to adopt Single Sign-On, but which provider to use. Keycloak and Microsoft Entra ID are the two options I evaluate most often, and the choice depends more on the company's context than on the technical features themselves.

Keycloak: control and flexibility

Keycloak is open source and self-hosted: it offers full control over realms, federated identity providers and authentication policies, plus the ability to customize themes and flows. It's the natural choice when independence from a single vendor's cloud is needed, or when the company already has an on-premise infrastructure to integrate with.

Microsoft Entra ID: native integration in the Microsoft ecosystem

When a company already uses Microsoft 365, Azure AD Connect or other Microsoft services, Entra ID drastically reduces integration effort: users, groups and security policies are already shared with the rest of the company's tools. The trade-off is less customization flexibility compared to a self-hosted solution.

Practical criteria for the choice

I mainly evaluate three factors: where user identity already lives (a Microsoft-centric company or a multi-vendor one), data residency and compliance requirements, and the maintenance workload the team is willing to take on independently. In many B2B/B2C projects the deciding factor is simply which identity system the client already has in production.

There's no one-size-fits-all answer: both solutions correctly implement OAuth2/OIDC and integrate well with REST backends. The real difference lies in the ecosystem the system needs to fit into, and that's where I start every time I design authentication for a new platform.