I applied through university. The process took 6 weeks. I interviewed at Jane Street in Sep 2017
Interview
I had one on campus interview. And then 3 phone interview. The interview questions were technical and mostly related to probabilities, expected values, law of large numbers, CLT, other statistics concepts.
Interview questions [1]
Question 1
What is the expected waiting time of having three consecutive heads?
They tend to examine the logical thinkers that can communicate clearly and concisely, and some problem-solving exercises intended to explore how you gather and apply new information, very different from other tech companies' interviews.
Initial application and online assessment. Had a first round behavioral interview where they asked me about myself, my experiences, and a couple of brain teasers. The interviewer was very nice.
Phone interviews (at least 3) - questions were of mixed difficulty (some pretty hard) but the interviewers were friendly and they gave helpful hints. Kind of fun - review probability and game-type questions.