Ory is described as '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' and is a identity management tool in the development category. There are more than 25 alternatives to Ory for a variety of platforms, including Online / Web-based, Self-Hosted solutions, Linux, Windows and Mac. The best alternative is Keycloak, which is both free and Open Source. Other great apps like Ory are FreeIPA, Auth0, FusionAuth and LoginRadius.
FreeIPA is an integrated security information management solution combining Linux (Fedora), 389 Directory Server, MIT Kerberos, NTP, DNS, Dogtag (Certificate System). It consists of a web interface and command-line administration tools.
FusionAuth is auth for any app. Get everything you need for secure registration and user management in minutes. Single-tenant, on-prem or private cloud, custom emails with localization, social login, and more.
10Duke Identity Provider makes it easy for your customers to access and register to multiple applications with single username and password or using their favorite social login, secures profile data and easily integrates with leading business tools.
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.