This is a related post that talks about the entity store that I built for my startup that was ultimately acquired by Twitter. They internally had their own similar store called ThriftStore that worked similarly. Google also builds their systems like this using protocol buffers. It is a pretty easy pattern and could theoretically be done with JSON if you provide some kind of schema and evolution strategy on read.

https://javarants.com/havrobase-a-searchable-evolvable-entit...