IdentityServer publishes a discovery document where you can find metadata and links to all the endpoints, key material, etc.

You can use the following clients (see here for the code definition).

Click here to manage your stored grants.

Diagnostics here

client id: m2m
grant type: client credentials
client secret: secret
access token lifetime: 60 minutes
allowed scopes: api

client id: m2m.short
grant type: client credentials
client secret: secret
access token lifetime: 75 seconds
allowed scopes: api

client id: interactive.confidential
grant type: authorization code with PKCE and client credentials
client secret: secret
access token lifetime: 60 minutues
allowed scopes: openid profile email api offline_access

client id: interactive.confidential.short
grant type: authorization code with PKCE and client credentials
client secret: secret
access token lifetime: 75 seconds
allowed scopes: openid profile email api offline_access

client id: interactive.public
grant type: authorization code with PKCE and client credentials
access token lifetime: 60 minutues
allowed scopes: openid profile email api offline_access

client id: interactive.public.short
grant type: authorization code with PKCE and client credentials
access token lifetime: 75 seconds
allowed scopes: openid profile email api offline_access

client id: device
grant type: urn:ietf:params:oauth:grant-type:device_code
access token lifetime: 60 minutues
allowed scopes: openid profile email api

You can call a test API at https://demo.identityserver.io/api/test.