XTX Markets Onsite Coding Interview

What the round is, what XTX Markets asks, and how to prepare, from candidate reports and the QuantVault practice set.

Stage 4 of 660 minUpdated October 20, 2026

The XTX Markets Onsite Coding interview is stage 4 of 6 in the XTX Markets interview process, after the Take-Home / Technical Data Round. Format: 60 min · live coding (Python / C++). Graded on correctness, edge cases, time/space complexity and, distinctively for XTX, numerical stability.

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What the Onsite Coding tests

Research-adjacent roles get numerical or data tasks (an estimator, a stable softmax / log-sum-exp, a clustering step, a streaming statistic) testing whether code survives floating point and large inputs. Confirm constraints, state complexity, narrate edge cases: clean, correct, explainable code beats a terse 'optimal' solution you cannot defend.

How to prepare for the Onsite Coding

Numerical stability counts. Log-sum-exp, avoiding catastrophic cancellation, divide-by-n-vs-n−1 — XTX-flavored coding rewards getting the math right, not just the algorithm.
State complexity up front and confirm constraints before you code. Then handle edge cases out loud.
Clean over clever. Readable, correct, well-named code beats a terse optimal solution you can't explain.

Further reading: How quant superdays work · C++ and low-latency interview questions · Behavioral questions at trading firms · Market-making game interview guide.

Prepare with QuantVault

PracticePractice the Onsite Coding roundRound notes and prep Interview funnelAll 6 XTX Markets roundsThe full funnel, a practice set for each stage Firm guideXTX Markets interview guideEvery round, tracks, timeline, pay and a prep plan Online assessmentXTX Markets online assessment guideFormat and practice Problem setXTX Markets interview questionsEvery question tagged to this firm CourseProbability course7 lessons Next roundOnsite Machine Learning / Research Deep-Dive60 min · whiteboard / discussion · QR & ML roles

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Frequently asked questions

What is the XTX Markets Onsite Coding interview?

It is stage 4 of 6 in the XTX Markets interview process, after the Take-Home / Technical Data Round. Format: 60 min · live coding (Python / C++). Graded on correctness, edge cases, time/space complexity and, distinctively for XTX, numerical stability. Research-adjacent roles get numerical or data tasks (an estimator, a stable softmax / log-sum-exp, a clustering step, a streaming statistic) testing whether code survives floating point and large inputs.

How long is the XTX Markets Onsite Coding interview?

Candidates report: 60 min · live coding (Python / C++).

How should I prepare for the XTX Markets Onsite Coding interview?

Numerical stability counts. Log-sum-exp, avoiding catastrophic cancellation, divide-by-n-vs-n−1 — XTX-flavored coding rewards getting the math right, not just the algorithm. State complexity up front and confirm constraints before you code. Then handle edge cases out loud.

What comes after the Onsite Coding?

The Onsite Machine Learning / Research Deep-Dive (stage 5 of 6). Format: 60 min · whiteboard / discussion · QR & ML roles.

Practice the XTX Markets Onsite Coding round

Open the round in the XTX Markets funnel: the round notes, prep, and every other stage of the process.

Practice the Onsite Coding round Create a free account XTX Markets interview guide XTX Markets online assessment All 6 rounds