Did the Jane Street NYC onsite in April 2026, senior SWE track. Full breakdown.
Format (my experience): 5 interviews over one day, roughly 8am-5pm with lunch 3 coding rounds, 1 system design, 1 behavioral Debrief same day for some loops, mine took 5 business days
Coding rounds: See my other post. Three 60-min live coding interviews. Clean code matters, complexity analysis expected, mid-problem pivots happen.
System design: 75 min, open-ended. Not the usual "design YouTube" template. More focused on a specific technical constraint, for me it was low-latency data processing under load. They want first-principles reasoning, not a predetermined architecture.
Behavioral: 60 min. Focused on intellectual honesty, technical judgment, and how you handle disagreement or uncertainty. They pushed on specifics.
What tripped me up: The third coding round. The problem looked easy at first. I jumped to a naive solution before fully reading the constraints. The interviewer let me go down that path for about 10 minutes, then asked me to read constraint three again. I had to restart. Cost me a lot of time. The lesson: at Jane Street, slowing down to fully understand the problem pays off more than starting fast.
Logistics: Lunch was with a few engineers, low pressure, mostly about what it's like to work there I got a tour of the trading floor which was genuinely impressive Accommodation and travel were fully covered, no complaints there
Outcome: Ding. Recruiter gave me feedback that it was close and the system design round went well but one of the coding rounds was the gap. Felt honest, not boilerplate.
Happy to answer specific questions.