Version 6.x has been out of support since May 14, 2024, and this corresponding section of the documentation is no longer maintained. We strongly recommend you upgrade to the latest supported version of 7.x and read the latest version of this documentation.
Duende IdentityServer issues tokens for accessing resources.
These resources are very often HTTP-based APIs, but could be also other “invocable” functionality like messaging endpoints, gRPC services or even good old XML Web Services. See the issuing tokens section on more information on access tokens and how to request them.