Under the hood we are just postgres. At the moment every user is on their own Postgres database with some additional plugins and defaults: https://github.com/supabase/postgres
We are already working on High Availability, and we'll give a very simple point-and-click for replication too (so you can create multiple DB's close to your customers/audiences)
Right now when a user creates a "project" we spin up a full server for them.
> Any issues with maxing out connections to the DB?
There are by default 100 max_connections. But if you use our libraries there is no problem - all requests get funneled through 1 server (which we will autoscale in the future). You'd be lucky to reach 10 connections. If you connect to the database yourself then it's really up to you how many connections you consume
