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Jane Street interview guide

Quant trading firm built on OCaml. SWE interviews are collaborative, multi-part practical coding problems in any language, judged on process and clarity. Updated October 2026.

Jane Street at a glance
Category Finance and quant
Intern level Software Engineer intern: Summer Internship (NYC May to August, London June to September, Hong Kong and Singapore May to August, per Oct 4, 2026 listings; official: internships typically run 10 to 12 weeks between May and September) and a Winter Co-Op (NYC, January to April; posting says 'Must be enrolled in a co-op program'). First/second-year programs (FTTP, FOCUS, Bridge, INSIGHT, WiSE, SEE, Preview, IN FOCUS) are separate from the internship; IN FOCUS dates are moving to May 2027.
New grad level Software Engineer (Full-Time: New Grad), listed for NYC, London, Hong Kong and Singapore on Oct 4, 2026. Jane Street publishes no level ladder; Levels.fyi tracks placeholder levels L1 to L4 and new grads report as L1.
0 to 3 years Software Engineer (Full-Time: Experienced). Same title; same core coding loop. Levels.fyi: L1 is entry level and L2 is typically 3 to 4 yrs experience, so 0 to 3 yrs maps to L1 or early L2.
Online assessment Usually none for US SWE intern and new grad. HackerRank when used. : When present: HackerRank coding test (London screening per 2020 official blog; first/second-year program in Oct 2025). Asia campus 2027-grad OA (Sep 2026) included a hard combinatorics-on-trees problem. Trading candidates get probability OAs (a Hong Kong SWE candidate was redirected to quant trading and given a 4-question probability test, Nov 2025).
Coding rounds 1 to 2 screens + about 4 onsite rounds (new grad); 1 to 2 screens + 2 to 4 onsite rounds (intern).
Behavioral No formal framework. Collaboration and communication are evaluated inside every coding round; short 'tell me about yourself' and 'Why Jane Street?' segments.
Timeline Rolling all year; no weekend interviews. Recruiter contact in days, first interview about 2 weeks to 1 month after applying (2025 intern reports), final invite within days of passing the screen, feedback within one week (official). Interviewing.io estimates about 4 weeks end to end. No hiring committee is publicly described; team placement happens after the offer. Reapply after about one year if rejected (official). Jugal's HFT post: quant applications open as early as June to August and many close by September to October, so apply early.
New grad pay Official (Jane Street job listings, Oct 4, 2026): NYC new grad SWE 'Base salary is $300,000' plus an annual discretionary bonus; the NYC SWE summer intern listing also states 'Base salary is $300,000' (annualized rate). Levels.fyi (US, updated Oct 4, 2026, 180 SWE submissions): L1 median total comp $363K (base $284K, bonus $75K, stock about $3K); overall SWE median $420K. Levels.fyi base figures lag the posted $300K base.
Official links Careers, Students, Official interview prep, Values

Interview process

New grad

  1. Application. Apply on janestreet.com (rolling, no typical deadline, no GPA or degree requirement; the free-text box on the application can be left blank). One application is considered for every open role and office globally. Official: you can expect to hear from a recruiter 'in just a few days' (interviewing FAQ); the SWE prep page says Jane Street responds to every application, 'ideally within a week or so'.
  2. Recruiter call (sometimes). Short background and motivation chat ('Why Jane Street?'). Experienced candidates may get a non-technical phone interview about career goals (2020 official blog).
  3. Technical screen (1, sometimes 2). Official: 'a technical interview that takes place over Zoom'. About 45 to 60 min, shared editor (CoderPad reported; one Jan 2025 new grad reported HackerRank), 1 to 2 Jane Street engineers. One practical problem in several parts: build a class or data structure, then extend it (key-value store, ETF fair value, order matching, Tetris). Real code in a real language, not pseudocode. A Oct 2025 NY report had two 45-min phone rounds.
  4. Final round (in person). Official: 'final-round interviews in person in one of our offices'. Usually 4 coding interviews (2 before lunch, 2 after), each about 60 to 75 min with two engineers. Candidates report being sent home after 2 rounds if those go poorly. Travel and hotel paid. Mostly or exclusively collaborative coding; London experienced loops reported 2 coding + 1 system design + 1 presentation (Sep 2025).
  5. Decision and placement. Official: you should hear back within a week of interviews. Hiring is centralized: interviewing.io says you are matched to a specific team after you pass the onsite. For interns, Jane Street's Jan 2022 blog describes a preference Zoom call in the weeks before the internship and pairing with a project the team needs.

Intern

  1. Application. Same portal, rolling review. Summer SWE internships in NYC, London, Hong Kong, Singapore (Oct 4, 2026 listings). Interns in 2025 came from 103+ universities and 24 countries (official).
  2. Online test (program and region dependent). Most US SWE intern reports say no OA: application, then a live interview about 2 weeks to 1 month later. HackerRank tests reported for first/second-year programs (Oct 2025), the London process (2020 official blog) and Asia campus hiring (India 2027-grad 'SWE Quant OA', Sep 2026).
  3. Technical interview (1 to 2). 45 to 60 min on Zoom/phone with a full-time engineer, CoderPad-style editor. Class-design and dictionary problems, 'not really algo-heavy' (Aug 2025). Strong performers are invited to the final within days.
  4. Final round (in person). 2 to 4 coding rounds with two engineers each; candidates report the day includes lunch and paid travel and hotel, and that you may be sent home after 2 rounds. London 2025 intern with an offer: 3 onsite coding rounds, all unseen non-LeetCode problems. UK Oct 2025 intern: two one-hour rounds before lunch, rejected after those two.
  5. Placement. Weeks before the internship a software engineer runs a Zoom call on your preferences (area of firm, kind of work, team style) and pairs you with a project the team actually needs (official blog, Jan 2022). Interns learn OCaml on the job; some teams use Python.

With 1 to 3 years of experience

Same collaborative coding core. Additions reported for 1 to 3+ years: a non-technical phone call on career goals (official 2020 blog), longer design-flavored rounds (interviewing.io: three 75-min coding/system design hybrid rounds in CoderPad plus a 75-min technical project deep dive), and in London a system design round and a presentation (Taro, Sep 2025). A Hong Kong Data Engineer (2.1 yrs, Mar 2026) got a practical problem-solving round (login-failure streaks). Jane Street says it does not test finance or OCaml knowledge. Official reapply guidance for experienced hires: wait until your experience or circumstances have significantly changed.

Online assessment

  • Platform: Usually none for US SWE intern and new grad. HackerRank when used.
  • Format: When present: HackerRank coding test (London screening per 2020 official blog; first/second-year program in Oct 2025). Asia campus 2027-grad OA (Sep 2026) included a hard combinatorics-on-trees problem. Trading candidates get probability OAs (a Hong Kong SWE candidate was redirected to quant trading and given a 4-question probability test, Nov 2025).
  • Notes: Aced (formerly Exponent) intern guide describes the loop as recruiter call, technical screen, final round, with 'no algorithm-screening stage'. A Sep 2025 NY intern report says 'There was no OA'. Do not assume a test; prepare for a live screen. The London HackerRank pre-screen is documented only in the 2020 official blog and may be outdated.

Prepare with How to pass an OA and compare formats in OA formats by company.

Coding rounds

  • Rounds: 1 to 2 screens + about 4 onsite rounds (new grad); 1 to 2 screens + 2 to 4 onsite rounds (intern).
  • Style: Practical, open-ended, multi-part problems that grow as you go: implement a class or data structure, then add requirements (eviction, rollback, matching, fair value). Official: avoids 'algorithm bingo and puzzles with clever aha solutions'. Difficulty about LeetCode medium; the bar is clean, correct, well-explained code. A Hong Kong SWE intern candidate on Aced recommended LeetCode's design problem list as 'the closest to Jane Street's style I can find'.
  • Environment: Shared online editor (CoderPad reported; HackerRank in some screens). Final rounds in person, typically two interviewers. Candidates report being expected to run and test their code (Oct 2025). Any language; official advice is to use your most familiar one, never OCaml just to impress.
  • Graded on: Official four traits: be nice, be clear, know your language ('comfortable with basic data structures and APIs in your language of choice'), know what you don't know. Process over final answer (official: how you get through the interview matters more than the snapshot of the solution at the end). Careful, clear code beats fast sloppy code (2017 official blog).
  • Reported focus topics: Class and API design that evolves over 3 or more parts, Hash maps and dictionaries, queues, ordered maps, trees, Caching and eviction (memoization, FIFO, LRU in O(1)), Simulation and game logic (Tetris, grid games), Trading-flavored modeling: order books, order matching, fair value, transaction rollback, Writing correct code fast in your strongest language and testing it, Clear spoken reasoning, clarifying questions, taking hints

Run every practice problem through the 45-minute framework and the code quality rubric.

What they ask (data)

Based on 1 distinct problems tagged to Jane Street in the last 6 months (0 in the last 30 days, 0 in the last 3 months, 15 all-time) across two open datasets of LeetCode company tags. Tags are user-reported, so treat frequency as a signal, not a promise.

Difficulty mix (last 6 months): Medium 100%

Most tagged topics (share of problems): Linked List 100%, Math 100%, Recursion 100%

Watch out: Jane Street has thin LeetCode data. Weight the reported questions and the format notes above more than this list.

Most frequent problems

Ranked by frequency, weighted toward the last 30 days. Classics like Two Sum sit near the top of almost every company's list because users tag them everywhere. Solve those fast. The signature list below is more specific to this company.

# Problem Difficulty Last seen Topics
1 Add Two Numbers Medium 6 months Linked List, Math, Recursion

Reported in 2025 to 2026 interviews

Questions candidates said they got, each linked to the post where it was reported.

Question Role When Source
Implement a class that stores and manages key-value pairs (distributed web systems flavor) SWE Intern, US 2025-10 post
Class design and dictionary-style problem, not algorithm-heavy (first-round screen) SWE Intern, New York 2025-08 post
Build out an ETF class and calculate fair values SWE, New York (process: two 45-min phone rounds, then onsite; round for this question not stated) 2025-10 post
Design an order book system from scratch. What would its APIs look like? SWE, candidate located in Australia (offer) 2025-08 post
Create Tetris (basic OOP) SWE Intern, US 2025-09 post
Match a buy order with the cheapest price in a database SWE Intern, US 2025-09 post
BuyerMarketplace: given a datastore of listings and a buyer's wants (item to max price), buy the cheapest unsold listing per item within budget and persist the trade (post shares only the candidate's solution code; round not stated) SWE (role not stated) 2025-09 post
Roll back transactions from a trading-simulation day SWE Intern, New York 2025-11 post
Design a distributed system class SWE, US 2025-10 post
Tree data structure problem (about LeetCode medium) in a live HackerRank round New Grad SWE, New York 2025-01 post
String manipulation and line arrangement problem (easy), after a HackerRank test SWE, first/second-year program, US 2025-10 post
LeetCode-medium-style task: write two functions; solvable with one loop and two dictionaries SWE, US 2025-11 post
OA: rooted directed tree of N tokens; for each position i, count tokens that can occupy position i in at least one valid dependency order (topological order) SWE/Quant OA, 2027 grad (India campus per post title) 2026-09 post
Live coding of several algorithms as parts of one combined software system SWE Intern, Canada 2025-11 post
Given users' login events (Success or Fail), flag users who failed exactly k times in a row (candidate compared it to Max Consecutive Ones) Data Engineer (2.1 yrs), Hong Kong, round 1 problem solving 2026-03 post

Beyond LeetCode

Every SWE round is a practical build: classes and data structures that evolve over several parts. Official worked example (2017 blog 'Memo'): memoize an expensive int to int function with a hash table, then fix unbounded memory with FIFO eviction in O(1), then discuss LRU in O(1) with a doubly linked list. 2025 reports: key-value store class, ETF class with fair values, order book design with APIs, buyer marketplace that buys the cheapest listing, rollback of a trading-sim day, Tetris. No mental math, probability, or logic puzzles for SWE (official), but trading and quant research roles have probability and market-making interviews (official trading guide PDF).

System design

No separate system design round for intern or new grad; design shows up inside coding as API and class design (order book APIs, 'design a distributed system class', key-value class). Experienced loops can include a design round and a project walkthrough (London Sep 2025; interviewing.io).

Start with who needs system design, then the framework.

Behavioral

Framework: No formal framework. Collaboration and communication are evaluated inside every coding round; short 'tell me about yourself' and 'Why Jane Street?' segments. (official page)

What they look for:

  • Be nice, be clear, know your language, know what you don't know (official prep page)
  • Humble and unafraid to ask questions and admit mistakes (official job postings)
  • Intellectually curious, collaborative, eager to learn (official job postings)
  • Asking great questions matters more than knowing all the answers (official interviewing page)
  • Clear, organized thinking and clean code under evolving requirements (2025 candidate reports)

Questions to prepare:

  • Why do you want to join Jane Street? (Hong Kong SWE, Nov 2025)
  • Tell me about yourself and the technologies you use (first/second-year program, Oct 2025)
  • Have you had experience with functional programming? (Canada SWE intern, Nov 2025)
  • Walk me through your past experience and the skills relevant to this job (Canada SWE intern, Nov 2025)

Build your answers with the story bank. Company detail: behavioral guide.

Tips

  • Watch Jane Street's official mock interview (https://www.janestreet.com/mock-interview/) and read the prep page first. A Sep 2025 intern said the real interview was 'very similar to the sample interview'.
  • Rehearse the official Memo problem end to end: memoize, add FIFO eviction in O(1), then LRU in O(1). Then drill LeetCode's design list (https://leetcode.com/problem-list/design/), which a Hong Kong SWE intern candidate on Aced called 'the closest to Jane Street's style'. Start with LRU Cache (https://leetcode.com/problems/lru-cache/).
  • Use the language you know best and know its standard library cold. Do not switch to OCaml or Python to impress; one Nov 2025 intern felt pushed into Python and struggled.
  • Write real, runnable code and test it as you go. Candidates in 2025 said you must be 'quick and correct' and that clean code mattered more than cleverness.
  • Talk the whole time. Restate the problem, confirm what the interviewer wants before optimizing, and treat hints as collaboration (Aced guide; official 'be clear' and 'know what you don't know').
  • Plan for an in-person final with two interviewers per round and up to 4 rounds. Bring stamina; you can be sent home after round 2.
  • Apply once; Jane Street considers you for every role and office. If rejected as a student, wait at least a year before reapplying (official FAQ); as an experienced hire, wait until your experience has changed.
  • Apply in summer. Jugal's HFT post: quant SWE applications open as early as June to August and many close by September to October (https://jugaldb.substack.com/p/how-to-break-into-300k-hft-roles).
  • Ask your recruiter about visa sponsorship early. Official FAQ: sponsorship 'changes from office to office, and depending on the role'.

4-week plan for Jane Street

Do this after you finish a core list like Grind 75 or NeetCode 150.

  • Week 1: Solve problems 1 to 20 from the most frequent list. Time-box each at 30 minutes.
  • Week 2: Solve problems 21 to 40. Re-solve any you failed in week 1 without looking.
  • Week 3: Solve problems 41 to 50 and every reported question above. Do 2 timed mock interviews.
  • Week 4: Write 8 stories for the No formal framework. Collaboration and communication are evaluated inside every coding round; short 'tell me about yourself' and 'Why Jane Street?' segments. round. Do 2 full mock loops. Review the online assessment and system design notes above.

Sources

Watch out: Fact-checked 2026-10-04: every URL re-fetched (janestreet.com pages and jobs/main.json via HTTP; Taro pages from server-rendered HTML; LeetCode posts and problem slugs through LeetCode's GraphQL API because leetcode.com returns 403 to scripts; Aced experience via a rendering fetch). Corrections made: removed a claim that the Jan 2026 LeetCode lateral-hire post says problems stay practical (the post is an unanswered question); the Aced 'design list' tip is from a Hong Kong intern candidate whose date is not shown in a static fetch (not confirmed as 2025); the team-placement preference call is documented for interns only; 'office tour' on the onsite was not supported and was removed; visa line replaced with the official FAQ answer. Candidates are asked not to share questions, so most reports are vague; titles above are paraphrases. Round counts vary by office and candidate (2 to 4 onsite rounds; 1 to 2 screens). OA usage varies: none in most US reports, HackerRank in London (2020 blog), first/second-year programs, and Asia campus hiring. Change to flag: finals are now in person (official prep page), unlike the remote Webex + CoderPad finals in the 2020 blog. Exponent rebranded as Aced. Jane Street publishes no level ladder; Levels.fyi levels are placeholders. The intern and co-op listings state 'Base salary is $300,000' as an annualized figure; actual pay covers only the internship period. Non-US listings (London, Hong Kong, Singapore) show no pay. The 2026 LeetCode Data Engineer report comes from an author whose post template matches a D. E. Shaw post from the same week; treat it as a single unverified anecdote. 1point3acres 2025 posts are login-gated and excluded.

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