I applied through university. The process took 5 days. I interviewed at Jane Street (Philadelphia, PA) in Jan 2016
Interview
First ask about question on your resume, and then mental math question, probability questions. At the end, you got a chance to ask about Jane Street. I simply ask them to describe their typical days working in Jane Street
The process began with serveral online tests for maths and logic. They gave a personal interview to get to know the candidate better and evaluate fit for the company/role, then held a technical interview covering maths and logic problems.
Fun and filled with unexpected questions. The questions rely on fast thinking and fast calculations, and sometimes intuition because there is no sufficient time for me to work through the whole problem.
We started with a bit of small talk, followed by some probability questions. Ended with some basic algebra questions, Make sure to ask questions if you have any. Good experience, feels like the interviewer was trading.