IdentityServer is a free, open source OpenID Connect and OAuth 2.0 framework for ASP.NET Core. Founded and maintained by Dominick Baier and Brock Allen, IdentityServer4 incorporates all the protocol implementations and extensibility points needed to integrate token-based authentication, single-sign-on and API access control in your applications. IdentityServer4 is officially certified by the OpenID Foundation and thus spec-compliant and interoperable. It is part of the .NET Foundation, and operates under their code of conduct. It is licensed under Apache 2 (an OSI approved license).
For project documentation, please visit readthedocs.
IdentityServer is built against the latest ASP.NET Core 2.
- Install the latest .NET Core 2.x SDK
- Run
build.ps1orbuild.shin the root of the repo
For using IdentityServer with ASP.NET Core 1.x, you can use the 1.x packages of IdentityServer and this branch. Documentation for 1.x can be found here. The 1.x version is not maintained anymore.
If you need help with implementing IdentityServer4 or your security architecture in general, there are both free and commercial support options. See here for more details.
If you are a fan of the project or a company that relies on IdentityServer, you might want to consider sponsoring. This will help us devote more time to answering questions and doing feature development. If you are interested please head to our Patreon page which has further details.
Auth0 
Auth0 is an easy to implement authentication and identity management SaaS based on OpenID Connect/OAuth 2.0. Check out their quickstarts here.
Thinktecture AG
Ritter Insurance Marketing
ExtraNetUserManager
Intuit
You can see a list of our current sponsors here - and for companies we have some nice advertisement options as well.
IdentityServer4 is built using the following great open source projects and free services:
..and last but not least a big thanks to all our contributors!