3 phone screens and 4 on-site interviews. All of those were technical questions.

The recruiters were very helpful and they reached a decision really fast. I left the interview directly for the airport and heard the "no go" decision before I even reached the airport!

I do want to stress that Jane Street is known for its tough interview questions, and the fact that I didn't get it also suggests it's not easy. However, I think their traders' interview questions are much more difficult, at least for people without sufficient practice. The software questions are very do-able and not intrinsically harder than those at the hottest tech firms. So, just be very prepared and don't get as scared as I was.

Design a Tetris Game