OpenAI Interview Questions — Page 48

OpenAI·Software Engineer·Take-home Assignment

Jun 2026

Got a take-home style problem for a SWE role at OpenAI that was more data quality and ML evaluation than pure coding. Basically asked to write a mini pipeline to detect label noise and report metrics. No model training, just NumPy/Pandas and some clear thinking about thresholds.

Given binary classification predictions and ground truth labels, compute accuracy, precision, recall, F1, and ROC-AUC. Then explain why accuracy is a poor metric under class imbalance and suggest better alternatives.
Design a label-noise detection method that flags samples where the model is highly confident but disagrees with the label. Output the suspect indices, and then propose a workflow to validate and clean those samples.

“The metrics part was fine, almost too straightforward.”

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OpenAI·Software Engineer·Recruiter / HR Screen

Jun 2026

Went into the OpenAI recruiter screen feeling pretty okay about it and came out rejected, which I did not see coming until the last few minutes when the energy shifted completely. The questions covered a mix of background, behavioral, and some surprisingly technical territory for what I assumed would be a light intro call.

Why did you move from your previous company to your current one?
Are you authorized to work in the US, and would you be open to relocating to San Francisco?
How does the internal promotion process work at your current company?
Walk me through a project you worked on. If traffic suddenly increased 10x, what weaknesses would you expect to see?
How do you approach debugging a production issue?
Tell me about a time something you built failed technically.
How can retry logic help prevent a system from entering an error state?

“Pretty standard career trajectory question but I rambled.”

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OpenAI·Software Engineer·Onsite - Coding / Algorithms

Jun 2026

OpenAI SWE coding round, one meaty problem the whole time. It was basically a mini scheduling system for GPU credits and they wanted the full thing: implementation, complexity analysis, and tests.

Design and implement a GPU credit accounting system with three operations: grant credits to a user with an expiration timestamp, consume credits using a soonest-expiry-first policy, and query a user's non-expired balance at a given time. Use a per-user min-heap with lazy expiration, discuss time complexity, and write tests covering partial consumption across grants and fully expired credits.

“This looked manageable at first glance and then I realized how many edge cases were quietly hiding in it.”

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OpenAI·Software Engineer·Technical Phone Screen

Jun 2026

OpenAI SWE coding round where I had to implement something related to typing in a language, basically an IME-style problem. Details were sparse even in the original post so I'm going off memory here.

Implement a function that simulates typing in a language using an input method editor (IME) style system, and make it pass a set of provided test cases.

“The problem statement itself wasn't totally clear to me at first.”

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OpenAI·Software Engineer·Technical Phone Screen

Jun 2026

Interviewed for a software engineering role at OpenAI and got a coding question that was basically a mini systems design problem disguised as a Python exercise. Not the most brutal interview I've had but it required more thought than I expected going in.

Build an in-memory key-value store in Python with set, get, serialize, and deserialize methods. It should handle type fidelity for common Python types and gracefully deal with missing keys or bad serialized input. Include basic tests showing data round-trips correctly.

“I went with JSON over pickle pretty quickly because pickle felt like a trap for a production-adjacent context (arbitrary code execution, version issues).”

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OpenAI·Software Engineer·Technical Phone Screen

Jun 2026

Got a system design coding question for a SWE role at OpenAI, specifically around building an in-memory rate limiter with thread safety. The problem was well-scoped but had enough depth to go sideways fast if you picked the wrong algorithm or forgot about cleanup for idle keys.

Implement a thread-safe in-memory rate limiter supporting both sliding window and token bucket policies, with an allow(key, now_ms) API that works across many keys and handles memory cleanup for idle ones.

“The actual coding part wasn't the hard bit.”

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OpenAI·Software Engineer·Technical Phone Screen

Jun 2026

Interviewed for a SWE role at OpenAI and got a chatbot routing problem. Not the typical leetcode grind, more of a design-meets-implementation hybrid that felt closer to real product work than I expected.

Design and implement a message router for a chat channel with multiple bots (e.g. an away bot, a taco bot, a meeting bot), where each incoming message may trigger zero or more bots based on their individual rules, and responses must be returned in a specified priority order.

“The problem sounds manageable until you realize the bot trigger rules aren't given upfront.”

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OpenAI·Data Scientist·Technical Phone Screen

Jun 2026

Got a code review style question for a Data Scientist role at OpenAI where they handed me a Python script and asked me to tear it apart. Pretty technical for a DS interview but I guess that's OpenAI for you.

You're given a Python script that assigns users to experiment groups and triggers a free-trial offer. What bugs or data quality risks do you see, and how would you refactor it to make the assignment logic safer and more reproducible?

“This one tripped me up more than I expected.”

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OpenAI·Product Manager·Hiring Manager Screen

Jun 2026

Behavioral round with the hiring manager at OpenAI, focused heavily on mission alignment and AI safety values. The technical bar is cleared before you even get here, so the pressure is mostly about convincing them you actually care about AGI and aren't just saying the right words.

Why do you want to work at OpenAI specifically?
What's your personal view on AGI and when or how it might happen?
What does AI safety mean to you?
Your manager tells you to ship an AI feature without completing safety testing. What do you do?
Tell me about a significant failure or a time you got serious pushback on something you believed in.
Walk me through why you left each of your previous jobs.
Describe a time you had to align a cross-functional team or navigate a difficult relationship with a PM or partner team.

“The recruiter actually flags this one in advance, which should tell you something.”

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OpenAI·Machine Learning Engineer·Technical Phone Screen

Jun 2026

ML coding round at OpenAI where they hand you a PyTorch file and drill you on complexity analysis. Less about writing code, more about whether you actually understand what the operations cost under the hood.

Given two dense matrices A of shape (m, n) and B of shape (n, p), what is the time complexity of computing C = A @ B in Big-O notation, keeping m, n, and p as distinct variables?
What is the space complexity of the matrix multiplication C = A @ B? Distinguish between auxiliary scratch space and the memory used to store the output matrix C.
How does the complexity change when A is shape (b, m, n) and B is shape (b, n, p) and you compute a batched matrix multiply?
If the matrices were square (m = n = p = N), what is the complexity, and what is the lowest exponent any known algorithm achieves versus what libraries actually run?
If A is batched with shape (b, m, n) but B is a shared matrix of shape (n, p), can you avoid running b separate matmuls and what is the complexity?
How would the time complexity change if A were sparse with nnz nonzero entries rather than dense?

“My first instinct was to say O(n^3) and I had to stop myself.”

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