openiddict-core VS IdentityServer4

Openiddict is also an option. Check it out.https://github.com/openiddict/openiddict-core

To implement an OAuth server together with OpenID connect specification, I used a free and open source framework called Openiddict. You should checkout their GitHub repository at github.com/openiddict/openiddict-core. It is a nice and feature rich tool which help you get started very fast. However, comparing to alternatives like identity server, it needs more implementation rather functionalities coming out of the box.

You can use Openidict https://documentation.openiddict.com/, give it a try

Openiddict to create your own OpenID Connect server if you want to deep dive into auth https://github.com/openiddict/openiddict-core

If you do want a .NET IdP then you could look into OpenIddict but will require some hands on work, at a minimum authorisation controllers. If you're looking for something more out of the box OrchardCore's OpenId module might be better for you.

I personally prefer using Cookies with openiddict.

Also, the OAuth bit is very cool!! Do you plan to support OpenIddict it’s a free federated identity server.

Okta is a great example of an IdP, although there are many others. Auth0, Ping Federate, Amazon cognito, etc. OP also mentioned Identity Server, which is a framework for implementing your own IdP. I've also personally used an open-source library called [OpenIDDict[(https://documentation.openiddict.com/) to great success. I would highly recommend attempting to implement one of these providers as a learning exercise.

Found this 6 year old issue https://github.com/IdentityServer/IdentityServer4/issues/736 but I didn't quite get the solution and it sounded awfully complicated.

IdentityServer4 can provide a base infrastructure or serve as reference code if you're trying to create your own tokens for your own users.

Read up on IdentityServer, they also have good starter templates. Scott Brady has the best tutorials IMHO.

The old v4 of IdentityServer was free under the Apache license (https://github.com/IdentityServer/IdentityServer4), but newer versions went all commercial.

Here's a link to IdentityServer's Github repository, [check the samples folder](https://github.com/IdentityServer/IdentityServer4) for the different types of scenarios and code that is used, and you're off to the races.

If you want federated login, use OpenID Connect with ASP.NET Identity combined with IdentityServer4.

Please be aware that End of Support for Identity Server is in a few weeks, if you mean https://github.com/IdentityServer/IdentityServer4