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.
I applied online. I interviewed at Jane Street in Oct 2016
Interview
I've applied to the trader position.
He phoned me, ask me to tell him if I've already known one of the following tasks and not to use pen and solve in mind.
He was speaking really slow and clear.
I had a mistake in on of the problems and he told me think over once more.
After tasks he told me about trader's job and differences between available positions.
Interview questions [5]
Question 1
find the sum 1 + 3 + 5 + ... 99 (odd numbers below 100) = ?
some easy probability questions like there are 3 days and there is a probability of rain for them. Find the probability that there are at least 2 days without rain.
there is a grey cube 3x3x3 was colored into red (all of its edges) . Next it was splitted into 1x1x1 cubes. 1 of these small cubes was chosen uniformly and uniformly thrown on a table. Find the P of "You can't see any red edges on this small cube"
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.