Connect to Wix website database with 3rd party app

Hi all
I’m developing a desktop app (using Qt) that will be purchased by subscription. I’d like to use a wix website for purchasing. Can anyone tell me how to connect my app to my wix website database to query subscription status. (I assume HTTP protocol unless you can recommend something else). Code snippets would be much appreciated.
Thanks
Jeff

Expose and Access Site APIs
Use MyApi and MyApiClient to expose and access external APIs.

Appears to be just what I was looking for. Thanks.