We have a demo instance of IdentityServer3 on https://demo.identityserver.io.
I already used this for various samples (e.g. the OpenID Connect native clients) – and it makes it easy to try IdentityServer with your clients without having to deploy and configure anything yourself.
The Auth0 guys just released a nice OpenID Connect playground website that allows you to interact with arbitrary spec compliant providers. If you want to try it yourself with IdentityServer – click on the configuration link and use these settings:
In essence you only need to provide the URL of the discovery document, the client ID and the secret. The rest gets configured automatically for you.
Pressing Start will bring you to our standard login page:
You can either use bob / bob (or alice / alice) to log in – or use your Google account.
Logging in will bring you to the consent screen – and then back to the playground:
Now you can exercise the code to token exchange as well as the validation. As a last step you can even jump directly to jwt.io for inspecting the identity token:
The source code for the IdentityServer demo web site can be found here.
We also have a more client types preconfigured, e.g. OpenID Connect hybrid flow, implicit flow as well as clients using PKCE. You can see the full list here.
You can request the typical OpenID Connect scopes – as well as a scope called api. The resulting access token can then be used to call https://demo.identityserver.io/api/identity which in turn will echo back the token claims as a JSON document.