Quantitative Developer Interview Prep

The short answer: Quantitative developers build the research tools, data pipelines and trading systems that quant researchers and traders rely on, mostly in C++ and Python. Only some of the nine firms here use the Quantitative Developer title in the US, so the same work is often posted as software engineering. Six of them publish a general or software engineering interview process, but none publishes a loop for the Quantitative Developer title itself. Millennium lists only its campus stages, and Point72 and Jump Trading publish nothing, so their loops come from candidate reports. Two Sigma and HRT prohibit AI tools in interviews, and the other seven firms publish no rule. Last reviewed October 2026.

Quantitative Developer interview: quick answers

What quantitative developers do

The job sits between research and production. At Citadel, Quantitative Developers partner with investment teams to turn ideas into research and trading systems. At Two Sigma, Quantitative Software Engineers become authorities on the systems behind a research area and measure their work by its impact on trading models. Millennium and Point72's Cubist place many developers inside one portfolio manager's team, where they build the research platform, data pipelines and live trading tools for that team.

Some roles chase latency and others chase scale. HRT says its Trading Tech group's biggest challenge is latency and its R&D group's is scale, with Trading Tech about 70% C++ and R&D about 70% Python. Citadel Securities asks its Quantitative Research Engineers to turn models into ultra-low-latency C++, and Optiver's Equities/ETFs engineers build systems that react to exchange market data in microseconds or less. Jane Street is the outlier on language: even its Low-Latency Engineer role builds fast-trading systems mainly in OCaml. At the research end, Cubist postings are Python-first, and Citadel's Data Strategies Group builds alternative-data pipelines in Python.

Titles rarely match from firm to firm, so read the posting. Three firms post Quantitative Developer in the US. Millennium uses it across trading pods, Execution Services and IT, Point72 uses it mostly at Cubist, its systematic affiliate, and Citadel says its Quantitative Developers are also known as Quantitative Research Engineers, at both Citadel and Citadel Securities. Two Sigma's match is Quantitative Software Engineer, split by team. Jane Street and Optiver hire the work as Software Engineers in the US, and Optiver's one Quantitative Developer posting, in Amsterdam, is assessed as Core Software Engineer. D. E. Shaw's match is Software Developer in its Quantitative Strategies group. HRT hires software and research engineers, with Algorithm Developer as its research-leaning path. Jump Trading uses Quantitative Developer only in its Asia-Pacific trading teams, and its US match is Core Development software engineering.

How 9 companies run the quantitative developer interview

The short version of each process. Each company guide has the full detail, with links to the company's own pages, and says which parts come from candidate reports.

The interview types in depth

Online coding tests

Most loops start with a timed online test. HRT and Optiver publish theirs. HRT's is a take-home coding test where it tells you to test your code, including corner cases, because the sample tests are not complete. Optiver sends its assessment after shortlisting and allows one attempt every 8 months. Millennium names technical and non-technical assessments for campus hires without describing them. At Citadel, Two Sigma and D. E. Shaw, the test comes only from candidate reports and guides, and Jump Trading candidate reports say not everyone gets one.

Lengths vary a lot. Candidate reports put Millennium's test anywhere from 2 hours to a 24-hour notebook, and candidate guides describe Optiver's as long object-oriented simulation problems followed by a multiple-choice section. One candidate guide describes a 3-hour, one-question developer test at Point72, which another guide does not mention. For a long build-style test, get a simple version working first, then improve it and say what each method costs.

Treat the test like production code. Read the whole problem, work a small example by hand, write your own edge cases and leave time to run them. A correct, tested solution to fewer problems usually beats rushed attempts at all of them.

Coding and data structures

Every loop has live coding on data structures and algorithms. Citadel's campus rounds are 45 minutes, with Python and C++ as core languages. Two Sigma's three 60-minute interviews cover topics such as tree and graph traversal, recursion, hash tables and concurrency, and grade testing as well as code. HRT lets you choose C++ or Python and says it avoids trick questions.

Some firms make the round feel like working together. Jane Street's software engineering loop is collaborative coding from start to finish, in the language you know best, with no math or puzzles. Its problems are open-ended and grow in parts: a retired question it publishes starts with memoizing a function and ends at a bounded cache with eviction. Optiver describes its technical interviews as discussion-based problem solving with an interviewer.

A structure that works: restate the problem, ask about input size and edge cases, give a simple solution and its cost, then improve it while talking through memory and time. On a problem that grows in parts, get each part correct and clean before you move on. Test with a small case out loud before you say you are done. Citadel and Two Sigma both say to use hints when you are stuck, so take them.

C++, language depth and systems fundamentals

Low-latency roles test how code runs on real hardware. HRT says its engineering interviews judge systems fundamentals such as memory, I/O and process management, and candidate reports describe questions on OS internals, C++ pointers and references, and implementing a pool allocator. Citadel Securities says many of its engineering roles expect C++ at the onsite. Jump Trading candidate reports describe screens on operating systems, virtual memory and undefined behavior, and onsite questions on struct padding and implementing std::vector. Optiver's own tips name computer architecture, networking, concurrency and memory management.

Python-first teams go deep on the language instead. Millennium candidate guides describe questions on asyncio, threads versus processes and decorators, and Cubist postings ask for knowledge of numerical library internals.

Prepare to explain cache lines and data layout, what a system call costs, how atomics and memory ordering work, and why allocation on a hot path hurts. Practice building small pieces such as a ring buffer, an object pool and an order book, and say how you would measure each one.

Design and build rounds

Design rounds here are about trading systems more than web services. Citadel Securities' experienced onsite takes one problem, such as an order book, a matching engine or a market-data pipeline, through design, code, code review and discussion over four to five hours, with new requirements added during the day. Two Sigma's technical interviews can include a systems design exercise and object-oriented design patterns, and HRT's onsite includes technical design discussions. Optiver says its technical interviews cover systems design and wants you to ask about load, latency and edge cases and draw labelled diagrams. Candidate guides describe design rounds on market data or risk systems at Millennium, and on order books, feed handlers or backtest pipelines at Point72.

Start with requirements and assumptions, sketch a design you can defend, then build the core path first. Keep the code readable so a reviewer can follow it, and be honest about its limits. Citadel Securities says a partial system you understand beats a finished one you cannot defend.

Probability and quick math

Probability is a smaller part of developer loops than of trader or researcher loops, and firms differ. D. E. Shaw says its technical interviews can cover probability and mathematical statistics, and a 2025 candidate report describes a separate math interview. Jane Street says its software engineering interviews have no math or probability questions. Candidate reports mention probability questions at Citadel and in a Two Sigma intern onsite, and candidate guides describe probability, expected value and quick Python simulations in HRT's Algorithm Developer rounds. Millennium's intern posting asks for probability and statistics.

Be fluent with expected value, linearity of expectation, conditional probability and the normal approximation, and check answers with a quick simulation when you can.

Behavioral and project deep dives

Citadel's second campus round mixes technical and behavioral interviews, and Citadel Securities suggests preparing a story about how your internships drove business outcomes. Two Sigma's later interviews cover specific projects and your contributions, and it says to tell the interviewer when work is confidential. Optiver runs a behavioral interview with a recruiter and suggests the STAR method, and D. E. Shaw says to know every job and project on your resume in detail. For Millennium pod roles, candidate guides describe a final conversation with the team or Portfolio Manager.

HRT names shallow fundamentals as the most common reason candidates fail, and lists poor listening, arrogance and indifference among the others.

Prepare four or five stories with numbers: a production bug you owned, a performance problem you fixed, a tool others used and a time requirements changed. Say what you did yourself.

Pay in US job postings

US salary ranges from each company's own postings for this role, seen October 29, 2026. They are base salary unless the company guide says the posting lists total salary. Each company guide has the postings and links.

Entry-level paths

• Citadel: Quantitative Research Engineer PhD Intern (US) roles of 11 weeks and PhD Graduate (US) roles at both Citadel and Citadel Securities, plus Software Engineer intern and university graduate postings.
• Two Sigma: About 80 summer interns in New York across Quantitative Research and Software Engineering, plus campus software engineering hires and the NewTS onboarding program for recent graduates.
• Hudson River Trading: Summer 2027 software engineering and algorithm development internships, 2027 new-grad Software Engineer and Algorithm Developer roles, and winter and early talent programs in New York.
• Jane Street: Software Engineer internships of 10 to 12 weeks in New York, London, Hong Kong and Singapore, new-grad Software Engineer roles in all four offices, and Tools and Compilers internships for PhD and master's students.
• D. E. Shaw: Software Developer Intern and Software Developer, Ph.D. Intern roles of 12 weeks in New York in summer 2027, with rolling applications and a recommendation to apply by the end of the previous calendar year.
• Point72: A Cubist Quantitative Software Developer internship in New York, a Summer 2027 Quantitative Developer Intern role in Internal Alpha Capture and a January micro-internship in Cubist Central Research Technology.
• Millennium: The 2027 Quantitative Developer Summer Intern role in New York, London, Hong Kong and Tel Aviv, which Millennium says it aims to hire its analyst class from.
• Jump Trading: The 10-week Campus Software Engineer internship in Chicago, which Jump calls the main way it finds young engineers for Core Development, plus campus C++ and Python internships in Asia-Pacific offices.
• Optiver: Open campus postings were in Europe when we checked: a 10-week Software Engineer Internship in London, the Amsterdam summer internship and the five-day Career Kickstarter: Tech program. US campus postings were closed.

AI tools in quantitative developer interviews

Rules on AI differ by company, so ask your recruiter before every round.

Prohibited. Two Sigma's software engineering interview guide says: "Use of ChatGPT or any other AI tool is strictly prohibited." It adds that any perceived use could result in disqualification of your application. HRT's postings say: "Use of AI tools by an applicant during interviews or assessments is strictly prohibited, unless otherwise instructed or agreed upon." They add that HRT may end the interview, disqualify the applicant or rescind offers, and HRT's engineering blog says it does not welcome cheating candidates to interview again.

No published rule. Citadel, Jane Street, D. E. Shaw, Point72, Millennium, Jump Trading and Optiver do not publish a rule on AI use in interviews; ask your recruiter. Citadel's student program terms ban generative AI for program application content, which applies to those programs and not to job interviews, and the Citadel Securities onsite page lets most candidates use their own editor, language and tools without mentioning AI assistants. D. E. Shaw's closest rule is that a requested writing sample must be entirely your own work, unedited by anyone else.

On the job, AI is often expected. Two Sigma's Techniques Engineering posting lists AI coding tools among its required skills, and Citadel Securities describes large language models as an important tool in a quant development intern's research workflow. Several Millennium postings expect AI-assisted development, Jump Trading's campus postings list AI tools as a plus, and Optiver's Career Kickstarter: Tech program teaches AI-assisted development. None of this says what an interview or assessment allows.

A 6-week prep plan

Courses for each round

• Modern C++
• Data Structures and Algorithms
• Trading Systems Design
• System Design
• Probability for Quant Interviews

Practice questions

Questions from our bank, then practice prompts from the company guides.

Company guides

Read the guide for each company you are interviewing with:

• Citadel: The Citadel Quantitative Developer interview at Citadel and Citadel Securities: the shared campus process, the one-problem experienced onsite, titles and posted pay.
• Two Sigma: Two Sigma hires quantitative developers as Quantitative Software Engineers. Its published guide covers software engineering in general: three 60-minute technical interviews and a strict AI ban.
• Hudson River Trading: Hudson River Trading (HRT) hires quantitative developers as software and research engineers. The loop is a coding test, phone screens and a full-day onsite, with AI tools prohibited.
• Jane Street: Jane Street hires developers as Software Engineers. The loop is a Zoom coding interview and in-person final rounds of collaborative coding, with no math or puzzles.
• D. E. Shaw: D. E. Shaw hires quantitative developers as Software Developers in Quantitative Strategies. The loop is a phone interview and virtual interviews on algorithms, programming and probability.
• Point72: Point72 hires quantitative developers mostly at Cubist, its systematic affiliate. It publishes nothing on the loop, so this guide labels every stage as unconfirmed.
• Millennium: Millennium hires Quantitative Developers into trading pods, Execution Services and IT. Here is the published campus process, what candidates report and the posted New York pay.
• Jump Trading: Jump Trading posts Quantitative Developer only in Asia; US developers join Core Development. Here is what candidates report about the loop and what the postings pay.
• Optiver: Optiver hires quantitative developers as Software Engineers. The loop is an online assessment, a behavioural interview and technical interviews, and US postings list a $200,000 base.