Implementing Single Sign-On (SSO) can be a powerful solution for streamlining authentication processes and enhancing security. While there are many commercial SSO solutions available, there are also free and open-source tools that can help you implement SSO in various environments. Here are some free SSO tools:

  1. Keycloak:
  • Description: Keycloak is an open-source Identity and Access Management solution. It provides features such as Single Sign-On, Identity Brokering, and User Federation.
  • Website: Keycloak
  1. Shibboleth:
  • Description: Shibboleth is an open-source project that provides Single Sign-On capabilities. It is particularly well-suited for federated identity solutions and is widely used in the academic and research community.
  • Website: Shibboleth
  1. SimpleSAMLphp:
  • Description: SimpleSAMLphp is a PHP-based application that provides support for SAML-based Single Sign-On. It is easy to set up and can be used as both an identity provider and a service provider.
  • Website: SimpleSAMLphp
  1. Auth0 (Free Tier):
  • Description: Auth0 is a widely-used Identity-as-a-Service (IDaaS) platform. While it has commercial plans, it also offers a free tier with limited usage that includes Single Sign-On and social identity provider integrations.
  • Website: Auth0
  1. Gluu Server:
  • Description: The Gluu Server is an open-source identity and access management platform. It supports various authentication protocols, including OpenID Connect and OAuth.
  • Website: Gluu Server
  1. FreeIPA:
  • Description: FreeIPA is an integrated Identity and Authentication solution for Linux/UNIX environments. While it is not solely an SSO solution, it provides features for centralized identity management.
  • Website: FreeIPA

Remember that the suitability of these tools depends on your specific requirements and the complexity of your environment. Additionally, the implementation and configuration of SSO can vary, and you should carefully review the documentation of the chosen tool to ensure it meets your needs.