Because PostgreSQL Is fantastic Open Source database engine, very popular with a lot of operational experience and tooling support.
This is Open Source way of doing things - having project focus on as narrow problem as possible (first) and leverage as much of existing componets as possible.
Ok, that makes sense. I guess this project is targeting a compatible frontend for multiple backends. When I saw MongoDB alternative, I thought they were building both sides of the coin.
Cramming an api for one product on top of another is absolutely not “the open source way” I’d expect a much better explanation for this Frankenstein’s monster. This seems like it would work but never scale.
Just a few of the things you need to build if you don't do it this way. 1. A storage layer, 2. A network protocol with clients and servers, 3. A replication system, 4. an authentication system. 5. Administrative tools.
If you roll everything yourself, you pretty much have to reinvent everything PostGres has except the SQL and relational aspects.
This is Open Source way of doing things - having project focus on as narrow problem as possible (first) and leverage as much of existing componets as possible.