Hudson River Trading (HRT) is an algorithmic trading firm that builds its own trading systems and research platform. Its engineering interviews are known for demanding algorithm problems and serious C++ and systems depth. This page covers what Hudson River Trading builds and who it hires, the process candidates commonly report, the technical depth the teams care about, representative problem types, what interviewers score, and a three-week prep plan.
What Hudson River Trading builds and who it hires
HRT trades across many markets using automated strategies, so its engineers build the trading systems, research infrastructure, simulation and data platforms that strategies run on. Roles include software engineers, algorithm developers who mix research and engineering, and hardware and systems specialists.
- Software engineers: trading systems, infrastructure and tools.
- Algorithm developers: strategies built on research and code.
- Systems and networking engineers: Linux, networks and performance.
- Hardware engineers: FPGA and low-latency hardware.
What the process tends to look like
| Stage | What happens | How to prepare |
|---|---|---|
| Online assessment | Commonly reported for students and new grads: a timed coding assessment of algorithm problems | Timed problems with hidden test cases; check edge cases before submitting |
| Phone or video interviews | Technical interviews with hard algorithm problems, followed by questions on cost and correctness | Explain approach and complexity before coding |
| Final round | Several interviews mixing algorithms, C++ and systems, with team conversations | Rehearse systems depth and one project deep dive |
Processes differ by team, level and office and change over time, so treat this as the common shape candidates report and confirm the specifics with your recruiter.
Algorithms, C++ and low latency
Hard algorithms. Expect problems at the harder end of the usual range, where the right data structure turns an impossible complexity into a fast one.
Low-latency C++. Know object layout, virtual dispatch costs, templates versus runtime polymorphism, cache lines and false sharing, and why allocation on the hot path is avoided.
Systems. Questions may cover Linux, networking (TCP versus UDP, multicast market data), and measuring performance rather than guessing.
Representative problem types
These are the kinds of problems candidates describe, not a leaked question list. Practice the category, not the exact question.
- Maintain an order book that supports fast inserts, cancels and best-price queries.
- Compute a sliding-window statistic over a stream in constant time per update.
- Design a lock-free single-producer, single-consumer queue.
- Parse a binary market-data feed efficiently.
- Shortest path or dynamic programming problems with tight limits.
- Explain the cost of a virtual call or a cache miss in a hot loop.
- Find the bug in a short C++ snippet involving lifetimes.
What interviewers score
- Correctness first: edge cases, overflow and off-by-one errors matter more here than elsewhere, because a bug costs money.
- Speed of reasoning: how quickly you reach a correct approach and how you check it.
- Low-level understanding: what your code costs in memory, cache misses and system calls.
- Clear thinking under pressure: saying what you are unsure of and how you would test it.
The behavioral side
Technical rounds decide most outcomes, but every Hudson River Trading loop also asks about how you work. Prepare a short story for each of these, with a result and what you learned:
- A mistake you made and what you changed. Trading firms value people who own errors quickly, because errors cost money.
- A decision under uncertainty. Explain what you knew, what you did not, and how you updated.
- Why trading, and why this firm? Be specific about the problems that interest you: speed, markets, research or infrastructure.
Structures and sample answers for the common questions are in our software engineer behavioral answers guide.
A three-week prep plan
- Week 1: algorithms at speed: two medium or hard problems a day under a 30-minute limit, with complexity stated aloud.
- Week 2: systems depth: C++ memory and object layout, concurrency primitives, Linux and networking basics, plus probability practice if the role touches trading.
- Week 3: mixed mock interviews, one per day, and a review of every bug you made so you stop repeating them.
For other trading firms, compare Jane Street, Citadel and Two Sigma, and read the Citadel online assessment for a typical HackerRank screen.
Where CoPilot Interview fits
Most of a Hudson River Trading loop is spoken: you explain an approach, defend a trade-off and talk through your past work. CoPilot Interview is an AI interview assistant whose free AI mock interview builds technical and behavioral questions from your résumé and the job description, reads them aloud and scores each spoken answer out of ten, so you can rehearse the explanation as well as the code. The free plan gives 15 minutes a day of live help in sessions of up to 15 minutes, with AI mock interviews included. Online assessments and many coding rounds forbid outside help, so practice beforehand and follow your employer's rules on the day.
Disclosure: CoPilot Interview is our product, so weigh what we say about it accordingly.
Frequently asked questions
What programming language should I use in a Hudson River Trading interview?
C++ and Python are the main languages; C++ matters most for systems and low-latency roles. Use the language you are strongest in for algorithm rounds unless told otherwise.
Does Hudson River Trading send an online assessment?
Candidates applying for student and new-grad roles commonly report a timed coding assessment early in the process. Experienced hires may go straight to interviews.
How should I prepare for Hudson River Trading coding questions?
Practice the problem categories above under time limits, explain every solution out loud, and spend the last week on the team's domain. Review the C++ or language fundamentals the role lists, because Hudson River Trading interviewers tend to follow a working solution with questions about cost and trade-offs.
Can I use AI tools in a Hudson River Trading interview?
Only if the instructions you receive say so. Online assessments and live coding rounds generally forbid outside help, and some companies now state their AI policy in the invitation. Use AI to practice beforehand, and follow your employer's rules.
Practice this interview before the real one
The AI mock interview builds questions from your resume and the job description, reads them aloud and scores each spoken answer out of 10. Included on the free plan.
Start a mock interview