I also played around with this. I wrote a little Postgres pooler/proxy in Go that used the actual Postgres frontend code hacked in as a library to parse queries

I also played around with this. I wrote a little Postgres pooler/proxy in Go that used the actual Postgres frontend code hacked in as a library to parse queries into an AST. I registered the pgfiddle.com domain. I lost interest in it though. I'm working some of the better things into a new project of mine, sqljoy.com (nothing there yet.) I've been developing it for over 8 months.