Hi John,
We don't have a supported Delphi client library. You may be able to get by with just an OAuth client if you are only looking for authentication (I'm not familiar with available Delphi libraries, but this looks promising: https://github.com/stievie/POAuth2 ).
If you find or write a Delphi library, please let me know, as I'd love to share it with our community.
Otherwise you have a few options:
* create a client. The client builder uses JSON, language specific files and Apache Freemarker to build the clients. The repository is here: https://github.com/FusionAuth/fusionauth-client-builder and we accept contributions
* file a github issue explaining what you'd like. We prioritize community input
* if you are in the position to pay, engage the FusionAuth team to build out a client library.
* use the API directly via HTTP(s) calls (this might be the simplest option).
Hope this helps. FYI, I'm a FusionAuth employee.