We have a number of options how you can experiment or get started with IdentityServer4.

Starting point
It all starts at https://identityserver.io – from here you can find all below links as well as our next workshop dates, consulting, production support etc.

Source code
You can find all the source code in our IdentityServer organization on github. Especially IdentityServer4 itself, the samples, and the access token validation middleware.

Nuget
Here’s a list of all our nugets – here’s IdentityServer4, here’s the validation middleware.

Documentation and tutorials
Documentation can be found here. Especially useful to get started are our tutorials.

Demo Site
We have a demo site at https://demo.identityserver.io that runs the latest version of IdentityServer4. We have also pre-configured a number of client types, e.g. hybrid and authorization code (with and without PKCE) as well as implicit and client credentials flow. You can use this site to try IdentityServer with your favourite OpenID Connect client library. There is also a test API that you can call with our access tokens.

Compatibility check
Here’s a repo that contains all permutations of IdentityServer3 and 4, Katana and ASP.NET Core Web APIs and JWTs and reference tokens. We use this test harness to ensure cross version compatibility. Feel free to try it yourself.

CI builds
Our CI feed can be found here.

HTH