I don't know if this counts as in production, but we use racket extensively on my team (we do predictive market simulations). I wish I could give you a deep te

I don't know if this counts as in production, but we use racket extensively on my team (we do predictive market simulations). I wish I could give you a deep technical reason why racket works where nothing else would do - but the truth is that I'm the one who picks the technology, and I like writing code in racket. biggest problems thus far are 1) the lack of external libraries (exempli gratia, nothing like python's boto for talking to ec2), but you probably saw that one coming. and 2) the language is almost too big, with too many datatypes: without even mentioning macros (which racket does quite well), the class/object system, the functional and mutable datatypes, contracts, pattern matching, typed racket, et cetera, can keep you pretty busy. Myself and the others might not just know racket well enough yet, but it's easy for one person to write unreadable code without ever leaving standard language constructs. But this is also the best thing about racket - the language is flexible enough that you can find a natural way to express whatever you need to. We've also been playing with distributed places (racket processes on remote machines) with some success, too.