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What to expect in a Jane Street interview

Jane Street interview research for Software Engineer and Quantitative Trader, with 4 practice rounds across 2 role plans, example questions, and preparation advice.

Practice a Jane Street round
RoundHound
Updated 5 min read

How Jane Street interviews

Start with the reported process for your role, then use our practice rounds to rehearse the skills it tests. The number, order, and length of the exercises below describe our practice plans; they are not a confirmed interview schedule. Follow your recruiter’s instructions for your team and location.

Software Engineer
Entry-level · 2 practice rounds · 1 h 45 min of practice
Quantitative Trader
Entry-level · 2 practice rounds · 1 h 45 min of practice

Jane Street Software Engineer interview

Jane Street's own pages describe a technical interview over Zoom, then final-round interviews in person at one of its offices. Both are mostly about working through coding problems with your interviewer, in real code and in whichever language you know best. Jane Street says it doesn't ask software engineers mental math or logic puzzles. Reports differ on how many interviews each stage has and how long they run, so this plan practices one interview from each stage.

Our 2 practice rounds

45 min practice

Zoom coding interview

See whether you can turn your reasoning into working code on a medium problem, explain your choices as you go, and say plainly when you don't know something.

Practice focus: Tree or graph traversal task with a second part that adds a constraint. Data processing task such as ranking records, then changed input rules. Array or string problem with a follow-up on complexity.

Illustrative practice follow-ups: “Interviewer adds a constraint after the first solution works and asks how the code must change.”

Practice this round
60 min practice

Final-round coding interview

See whether you can keep your code clean and correct as one problem grows, and whether you work well with the person across the table.

Practice focus: Simple function that is later extended with new requirements and limits. Memoization or caching task followed by open design discussion. Implementation-heavy problem with a changing data model.

Illustrative practice follow-ups: “Interviewer asks for a different design when a new constraint breaks the current one.”

Practice this round

Jane Street Software Engineer interview questions

  • One or two live sessions of about an hour, with original problems solved in real time. Independent guide

What candidates and sources report

  • Jane Street's official pages describe a technical interview over Zoom, then final-round interviews in person at one of its offices. Both stages focus mostly on collaborating on coding problems. Jane Street
  • Candidates write real code, not pseudocode, in the language they know best. Jane Street gives no extra credit for OCaml and says not to use it if it isn't your strongest language. Jane Street
  • Jane Street says it prefers open-ended problems with several reasonable approaches, and that the journey through the interview matters more than the final solution. One of its tips is to know what you don't know. Jane Street
  • Jane Street's current preparation page says software engineers aren't asked mental math, math olympiad questions or logic puzzles. A 2020 Jane Street post said the same about math and probability. Jane Street
  • Jane Street says candidates should be comfortable with basic data structures and APIs in their chosen language. Its mock interview page suggests LeetCode and HackerRank for algorithmic practice, while noting their questions aren't exactly what Jane Street asks. Jane Street

How to prepare

  • Practice medium problems while talking them through: Solve tree, graph and array problems in one language. Say your approach first. Write real code. Walk through a sample input by hand.
  • Practice problems that grow: Solve a simple version, then add two new rules yourself. Change the code without rewriting it. Check the change by hand.

Mistakes to avoid

  • Don't go quiet while you think. Your interviewer can only follow the reasoning you share.
  • Don't guess when you're unsure. Say what you know and what you don't.
  • Don't use OCaml just to please the interviewer.
  • Don't rush to your first idea. Talk through at least two options first.
  • Don't patch code until it's hard to read. Refactor as the problem grows.

Questions to ask your interviewers

  • How many interviews are in the new-grad software engineer final round, and how long is each one?
  • Is there an online assessment before the first live coding interview for new-grad software engineers?
  • Which editor or tool do interviewers use for the Zoom coding interview?
  • Does the final round include a project discussion for new graduates?
Open the Software Engineer practice plan

Jane Street Quantitative Trader interview

Jane Street says its trading interviews start with phone interviews and end with in-person interviews. The final stage can cover problem solving, probability and statistics, coding in any language, data analysis and general interests, and Jane Street says it should feel more like a conversation than a quiz. Candidates report probability puzzles on the calls and dice, card and market-making games in person. The number and length of interviews aren't published, so this plan practices one phone interview and one in-person game interview.

Our 2 practice rounds

45 min practice

Phone interview: probability and reasoning

See whether you can solve probability and expected-value problems methodically, talk through your reasoning, check that your answer makes sense, and recover calmly from mistakes.

Practice focus: Classic coin, dice or card probability puzzle with a twist. Expected value of a simple game with a stopping choice. Estimation problem that needs a sanity check and a range you'd stand behind.

Illustrative practice follow-ups: “Change a game rule and ask how the answer shifts.”

Practice this round
60 min practice

In-person trading games

See whether you can price bets, quote markets, adjust when the other side trades with you, and keep explaining clearly while the rules change. The real final round may also include coding and data analysis, which this room doesn't cover.

Practice focus: Market-making game on a hidden sum from cards or dice. Dice or card betting game: decide whether to bet and at what price. Short data analysis or simple non-LeetCode coding task with discussion.

Illustrative practice follow-ups: “Offer a side bet that may create arbitrage, then ask you to adjust.”

Practice this round

Jane Street Quantitative Trader interview questions

What candidates and sources report

  • Jane Street's official page says the trading interview process starts with phone interviews and ends with in-person interviews. Jane Street
  • Jane Street's trading page says the final round may cover problem solving, probability and statistics, coding in any language, data analysis and general interests. Jane Street
  • Jane Street says the interviews should feel more like a conversation than a quiz. They need no finance knowledge and no math beyond what a higher-level college course would cover. Jane Street
  • Jane Street advises approaching problems methodically, communicating clearly, correcting your own mistakes and asking why. It also offers a mock trading interview video. Jane Street
  • Jane Street's Probability & Markets guide calls the interview a collaboration. A correct answer alone isn't enough, because the interviewer will want to hear how you got there. It's fine to say you aren't sure of an answer. Jane Street

How to prepare

  • Practice probability and expected value, talking it through: Solve dice, card and coin problems most days. Say each step as you go. Before the final answer, do a sanity check and say how sure you are.
  • Practice market-making games with a partner: Play card and dice sum games. Quote bid and offer, then react to partner trades. Review your fair value and spread logic.

Mistakes to avoid

  • Don't give a final number without showing how you got there.
  • Don't hide or defend a mistake once you spot it.
  • Don't quote a price without a fair value behind it.
  • Don't ignore what the other side's trade tells you.

Questions to ask your interviewers

  • How many phone interviews are in the entry-level trader process, and how long is each one?
  • Does the current process include an online mental-math or probability test?
  • How long is the final round, and which interview types does it include in my office?
  • Are final interviews in person for the office I applied to, or are some virtual?
Open the Quantitative Trader practice plan

Sources

Latest catalogue research: . Practice exercises and follow-ups are our own; they are not confidential interview questions.

Independent preparation using Jane Street as a practice target. Not affiliated with, endorsed by, or sponsored by Jane Street.

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