Jane Street Software Developer Internship interview questions

1) Applied online 2) Hour-long phone interview 3) Final round - 3 rounds of technical interviews, ~1-1.5 hours each Entire process took less than two weeks - I got my offer decision the afternoon of my final round. All of the questions were system design questions (write a class to ___), no LC-type questions anywhere in the process. All of the engineers were very friendly, and if there was anything I was initially stuck on I was able to talk through my thought process with them and eventually reach a solution. There was also a Q&A session with two SWEs after the last technical interview during the final round.