Connect2id Server is described as 'OpenID Connect / OAuth 2 server for single sign-on, identity provision and federation, and securing web APIs with access tokens. Supports profiles for fintech applications, eHealth, eGovernment and others'. There are more than 10 alternatives to Connect2id Server for a variety of platforms, including Self-Hosted solutions, Windows, Linux, Online / Web-based and Mac. The best alternative is Keycloak, which is both free and Open Source. Other great apps like Connect2id Server are CAS (Free, Open Source), LemonLDAP::NG (Free, Open Source), OpenAM (Free) and shibboleth (Free, Open Source).
LemonlLDAP::NG is a modular Web-SSO based on Apache::Session modules. It simplifies the build of a protected area with a few changes in the application. It manages both authentication and authorization and provides headers for accounting.
standards based, open source software for web single sign-on across or within organizational boundaries allowing sites to make informed authorization decisions for individual access of protected online resources in a privacy-preserving manner.
Ory builds cloud-native authentication (login), authorization (permission), delegation (OAuth2, OpenID Connect), and user management software. You can deploy what you need yourself or use the Ory Cloud Platform and get started in minutes.
SimpleSAMLphp is an application written in native PHP that deals with authentication. The main focus of SimpleSAMLphp is providing support for SAML 2.0 as a Service Provider (SP) and SAML 2.0 as an Identity Provider (IdP).