Shameless plug here, but my side-project (http://bedquiltdb.github.io http://bedquiltdb.github.io) aims to provide a nice mongo-a-like programmatic API on top o

Shameless plug here, but my side-project (http://bedquiltdb.github.io http://bedquiltdb.github.io) aims to provide a nice mongo-a-like programmatic API on top of PostgreSQL and JSONB. In theory there's no reason why we shouldn't be able to support a nice transactions API in the client drivers too, I just haven't gotten around to it yet.