Hello, I understand your requirements and appreciate for putting in the description.
As you wish it to be a document store we will set up the master table as JSON object.
Also as described in point number 2 we can create both an API or standalone java-lib that can be embedded in your existing project.
Let me know when can we start working on the project - via your attachment you desire to have the project finished in 13 days that is perfectly fine with us.
Relevant brief background about myself: Software Engineer with 9.5+ years of experience in Java, J2EE, Rest API, microservices, SpringBoot.
I will aim for your satisfaction, though an experienced programmer but new to the freelancer community.
Hope we will enjoy working together.
Best Regards
Siddharth