I use fixer in a client project (started back when it was free, now i think it's a couple bucks a month)... Never heard of Frankfurter, but if it's the same guy

I use fixer in a client project (started back when it was free, now i think it's a couple bucks a month)... Never heard of Frankfurter, but if it's the same guy that's super interesting and I too would like to know the backstory