Best Free and Open Source Alternatives to Microsoft Entra ID

Microsoft’s attitude towards open source software has changed considerably over the years. The company once regarded open source as a threat to its business, but it now contributes to open source projects, participates in organisations such as the Linux Foundation and maintains a growing collection of open source software.

Despite that shift, many important Microsoft products and services remain proprietary. For organisations and individuals who want greater control over their infrastructure, open standards and self-hosted services can offer compelling alternatives.

This series looks at the best free and open source alternatives to products and services offered by Microsoft.

Microsoft Entra ID, formerly known as Azure Active Directory, is Microsoft’s cloud-based identity and access management service. It provides centralised management of users, groups and applications together with single sign-on, multifactor and passwordless authentication, application federation and access policies. Microsoft also offers features such as Conditional Access, identity protection and identity governance around the core service.

Microsoft Entra ID is proprietary software delivered primarily as a cloud service. We recommend the best free and open source alternatives.

No individual open source project reproduces every part of the Microsoft Entra ecosystem. The alternatives below nevertheless provide strong identity management, authentication, single sign-on, federation and access-control capabilities.

1. Keycloak

Keycloak is my strongest recommendation. It is a comprehensive identity and access management platform designed to provide authentication and authorisation for applications and services.

It offers single sign-on and single sign-out together with OpenID Connect, OAuth 2.0 and SAML support. Existing LDAP and Active Directory directories can be federated with Keycloak, while identity brokering makes it possible to authenticate users through other OpenID Connect and SAML identity providers.

Authentication options include passwords, passkeys, one-time passwords, recovery codes and X.509 certificates. Administrators also get central management of users, groups, roles, applications and authentication flows.

Keycloak is particularly attractive as a replacement for the application identity, federation and SSO parts of Entra ID.

2. Janssen

Janssen is an enterprise-focused digital identity platform developed under the Linux Foundation.

It offers a broad implementation of modern identity standards including OAuth 2.0, OpenID Connect, SAML, FIDO2, SCIM and UMA. The platform supports multifactor authentication, passkeys, enterprise directory integration, user and group management, session management and detailed audit logging.

Janssen is built from multiple components. These include an authentication and authorisation server, FIDO2 support, a SCIM service for managing identity data and Casa, a self-service portal where users can manage their authentication credentials.

The software is designed with large deployments in mind and supports cloud-native deployment, including Kubernetes. It is one of the closest open source choices here for organisations looking for a broad enterprise identity platform rather than simply an SSO server.

3. Kanidm

Kanidm is a modern identity management platform designed to provide a central source of authentication and identity information for applications, services and systems.

It supports OAuth 2.0 and OpenID Connect for web authentication together with WebAuthn and passkeys. Role-based access control is built in, while RADIUS support makes Kanidm useful for network and VPN authentication.

Kanidm is particularly interesting for organisations with substantial Linux and Unix infrastructure. It provides PAM and NSS integration, offline authentication, SSH key distribution and an LDAPS gateway for applications that still expect LDAP.

The project puts considerable emphasis on strong authentication and reducing reliance on traditional passwords. It makes a compelling Entra ID alternative where central identity management needs to extend beyond web applications to Linux systems and network services.

4. FreeIPA

FreeIPA takes a somewhat different approach. It is an integrated identity, authentication and policy management solution aimed primarily at Linux and Unix networks.

The platform combines technologies including 389 Directory Server, MIT Kerberos, DNS, a certificate authority and SSSD. Administrators can centrally manage users, groups, hosts and services, while Kerberos provides single sign-on across participating systems.

FreeIPA also provides policies for areas such as sudo access, host-based access control and Kerberos authentication. Multiple servers can be deployed for redundancy and scalability, and trust relationships can be established with Microsoft Active Directory.

It is not a direct replacement for Entra ID’s cloud application ecosystem. However, for organisations using Entra ID primarily as part of a central identity infrastructure, FreeIPA is an especially strong option for Linux-heavy environments.

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Alternatives to Microsoft's Products and Services
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