Jane Street does not run a separate behavioral round for software engineers. Its prep page says the main thing interviewers decide is whether they would want to work with you, judged from how you think, communicate and take suggestions while solving coding problems together. The behavioral questions candidates do report are short: tell me about yourself, why Jane Street, whether you have functional programming experience, and questions you want to ask at the end of the final day.
The firm describes its ideal mindset as “persistent, humble, and curious.” In 2025 reports, interviewers suggested refinements and flagged issues while candidates coded, and one July 2025 New York intern reached a correct solution but still did not get an offer. Round details are on the Jane Street interview questions page and the Jane Street interview experience page.
How behavior is judged inside Jane Street coding rounds
| Moment in the round | What the interviewer sees |
|---|---|
| Reading the problem | Whether you ask clarifying questions or start typing |
| Choosing an approach | Whether you explain trade-offs between the several reasonable approaches |
| Getting a hint | Whether you take it and build on it, or defend your first idea |
| Hitting a bug | Whether you say what you think is wrong before changing code |
| Running out of time | Whether you say what you would do next and why |
Common Jane Street behavioral questions
1. Tell me about yourself
Reported as the opener of a 2025 New York intern’s first round. Sample answer: “I’m a third-year computer science student. Most of my coding is in Python and C++, and the project I know best is a scheduler for our university’s lab machines that cut average job wait from 40 minutes to 12. I like problems where the first version is easy and the follow-ups are hard, which is how your interviews were described to me.”
2. Why Jane Street?
Sample answer: “Two things. You build nearly everything in-house, so engineers own the trading and risk systems end to end instead of gluing vendors together. And trading, research and technology work closely, so I’d see how my code is used the same week. In my internship the best part was sitting with the analysts who used my dashboard; I want more of that.”
3. Do you have experience with functional programming?
Reported in a Cambridge, England intern interview. Sample answer (no OCaml): “Not in OCaml. I use map, filter and immutable data in Python and I’ve written a small interpreter in Racket for a course. I know Jane Street doesn’t expect OCaml at interview, and I’d learn it the way I learned Racket: small programs first, then reading real code.”
4. Tell me about a time you were wrong
STAR sample: “Situation: I designed a caching layer for a course project and was confident it was correct. Task: Ship it before the demo. Action: A teammate showed me stale reads under concurrent writes; I reproduced it with a test, admitted the design was wrong and switched to write-through. Result: The demo had no stale reads, and I now write the concurrent test before claiming something is safe.”
5. Tell me about a time you got stuck and how you got unstuck
Sample answer: “I spent a day on a segfault in a C++ parser. I stopped guessing, wrote the smallest input that crashed it, and ran it under AddressSanitizer, which pointed to a use-after-free in two minutes. Since then my rule is: after 30 minutes of guessing, shrink the input and use a tool.”
6. How do you take feedback on your code?
STAR sample: “A reviewer said my function did three things. I disagreed at first, then tried splitting it and found two of the pieces were reusable elsewhere. I merged the split version and started writing smaller functions by default.”
7. Describe a project where the requirements changed halfway
Sample answer: “Our club’s backtester was built for daily data; halfway through, the team wanted minute bars. Because I’d kept data loading behind one interface, the change touched one module and took two days instead of a rewrite. I learned to put the likeliest change behind an interface from the start.”
8. Tell me about a hard problem you kept working on
Framework: Jane Street lists persistence first in its mindset. Choose a problem that took days or weeks, show the dead ends you ruled out and how you measured progress.
9. When do you ask for help?
Sample answer: “When I’ve written down what I tried and still can’t form a new hypothesis, usually after an hour on a bug. Asking with that list saves the other person time.”
10. What would you like to learn here?
Sample answer: “How a trading firm tests systems where a bug costs money in seconds, and enough OCaml to read the codebase. I’d also like to understand how researchers and engineers agree on what a tool should do.”
11. Questions for us at the end of the day
A 2026 Glassdoor reviewer described a question-and-answer session after three final-round interviews. Strong questions:
- “How do new engineers learn OCaml in their first month?”
- “What does code review look like for a change to a trading system?”
- “How do engineers and traders decide what to build next?”
Answers that hurt at Jane Street
- Pretending to know something you don’t; Jane Street’s advice says the opposite
- Ignoring or arguing with an interviewer’s suggestion instead of trying it
- Choosing OCaml to impress when you are faster in another language
- A “why Jane Street” answer about pay or prestige
- Going silent while you code
Similar companies
Citadel · Hudson River Trading · Susquehanna (SIG) · D. E. Shaw · Arcesium