OneLogin is described as 'single sign-on (SSO) and identity management solution for businesses'. There are more than 10 alternatives to OneLogin, not only websites but also apps for a variety of platforms, including Mac, Windows, Linux and Self-Hosted solutions. The best alternative is Keycloak, which is both free and Open Source. Other great sites and apps similar to OneLogin are LoginRadius (Paid), Okta (Freemium), 10Duke Identity Provider (Paid) and Ory (Free, Open Source).
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.
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.
Cloud-based directory services. Alternative to Microsoft Active Directory. Provides LDAP-as-a-Service, RADIUS-as-a-Service. Authenticates, authorizes, and manages employees, their devices and IT applications.