[nojvek]

We started our startup on Mongo. Hit some pretty hard performance problems and eventually did a multi month long migration to Postgres (Aurora on AWS).

MongoDB is only a valid choice if all you're doing is story key document pairs. The moment you need joins or any sort of aggregations like count/sum e.t.c - Mongo perf is horrendous. Postgres runs circles around Mongo in every way.

With jsonb columns, not much is lost. SQL is a huuuuge bonus. Mongo query language is a giant pain for everyone on team to learn and manage.