First of all, a very informative document provided so writing APIs will not be difficult as the requirements are properly mentioned.
Secondly,
I have been working on the exact same combination of back end technology and database for a long time now.
I know how to write API in gin/gonic ,nethttp etc.
I am new to freelancer and only want to pickup projects that I can complete with a satisfactory result.
I can assure a scalable code with optimised functionalities.
I can also provide a dynamic schema (if required).
I can give you my full dedication towards the work.
It will be a pleasure working with you.
Regards
Akshat