I've frequently run into the issue of wanting to email a subset of users out of a database.
Usually I just run a query, and write a script to look though and send the notification. But I figured I could build a better solution! This is very much an MVP, so things are pretty fragile. But it works great for Postgres/Postmark!
Right now there's no DB attached. Database connections / API keys are stored in local storage, and sent along with queries.