AspNetCore.Docs/aspnetcore/includes/IdentityServer4.md

ASP.NET Core Identity adds user interface (UI) login functionality to ASP.NET Core web apps. To secure web APIs and SPAs, use one of the following:

• Azure Active Directory
• Azure Active Directory B2C (Azure AD B2C)
• IdentityServer4

IdentityServer4 is an OpenID Connect and OAuth 2.0 framework for ASP.NET Core. IdentityServer4 enables the following security features:

• Authentication as a Service (AaaS)
• Single sign-on/off (SSO) over multiple application types
• Access control for APIs
• Federation Gateway

For more information, see Welcome to IdentityServer4.