OpenAI Machine Learning Engineer Interview Questions

OpenAI Machine Learning Engineer interview questions typically probe both deep ML knowledge and practical engineering skills. Distinctive about OpenAI interviews is the strong emphasis on mission fit, model reasoning, and safety-aware decision making alongside reproducible code and scalable system design. Expect a mix of hands-on coding or take-home assessments, technical deep dives into past projects, architecture and infrastructure discussions (training pipelines, distributed training, inference), and scenario-based safety or ethics questions. Interviewers evaluate algorithmic thinking, experimental rigor, debugging instincts, communication, and collaboration. For interview preparation focus on three areas: refresh core deep learning and probabilistic foundations, practice clean, production-ready coding and algorithmic problem solving, and prepare a concise, critical deep-dive of a past project that highlights trade-offs and outcomes. Read OpenAI’s recent research and blog posts to situate your examples, and rehearse explaining failures and mitigations clearly. Mock technical deep dives and system-design rehearsals that include data, compute, and monitoring considerations often pay off.

75 Questions 1 Company06.27.2026
Showing 20 results
Role
OpenAI logo
OpenAI
Medium
Machine Learning Engineer Locked

Implement Masked Cross-Entropy with Label Smoothing

Implement numerically stable masked cross-entropy in NumPy with label smoothing and optional temperature scaling. Validate shapes, dtypes, finite logi...

Machine Learning
66
1
561 people solved
Jun 27, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer Locked

Implement 1NN with NumPy

This question evaluates implementing a 1-nearest-neighbor classifier with NumPy, testing skills in vectorized numerical computation, distance metrics,...

Machine Learning
287
3
2722 people solved
May 19, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Compute entropy and implement 1-NN

You are given two short ML coding problems from a machine-learning engineer screen. Both are implementation-focused but probe whether you understand t...

Machine Learning
121
1
1153 people solved
Apr 24, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Derive Sharded Matrix Multiplication and Backpropagation

Derive Sharded Matrix Multiplication and Backpropagation Consider Y = X @ W, where X has shape (B, D) and W has shape (D, H). Training runs on P devic...

Machine Learning
27
0
290 people solved
Apr 19, 2026
OpenAI logo
OpenAI
Hard
Machine Learning Engineer

Improve Training With Noisy Annotators

You are given a labeled training dataset as a Pandas DataFrame. Each row contains feature columns, an observed label, and an annotator_id identifying ...

Machine Learning
90
0
782 people solved
Apr 2, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Design a RAG system with evaluation

Scenario Design a Retrieval-Augmented Generation (RAG) system that answers user questions over a private corpus (internal docs, PDFs, knowledge-base a...

ML System Design
177
1
1701 people solved
Jan 6, 2026
OpenAI logo
OpenAI
Hard
Machine Learning Engineer

Improve classifier with noisy multi-annotator labels

Problem You are given a text dataset for a binary classification task (label in $\{0,1\\}$). Each example has been labeled by multiple human annotator...

Machine Learning
905
3
6118 people solved
Feb 11, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Debug MiniGPT and Backpropagate Matmul

This is a hands-on PyTorch screen with two independent tasks. You share a code editor with the interviewer and are expected to run the code, read trac...

Machine Learning
106
0
1062 people solved
Apr 3, 2026
OpenAI logo
OpenAI
Hard
Machine Learning Engineer

Compute Matrix Prefix Products And Gradients

You are given $N$ square matrices $A[0], A[1], \dots, A[N-1]$, each of shape $D \times D$. Define the inclusive prefix (cumulative) products: $$Y[i] =...

Machine Learning
77
0
795 people solved
Apr 2, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Debug a Concurrent Job Scheduler

You are handed a buggy Python job scheduler that runs many independent jobs concurrently. Each job has an ID, a callable to execute, a maximum retry c...

Software Engineering Fundamentals
48
0
396 people solved
Apr 3, 2026
OpenAI logo
OpenAI
Hard
Machine Learning Engineer Locked

Implement Backprop for a Tiny Network

This question evaluates understanding of backpropagation, gradient derivation, numerical stability of softmax cross-entropy, and practical implementat...

Machine Learning
175
0
1503 people solved
Apr 3, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Explain KV cache in Transformer inference

Question In Transformer-based large-language-model inference, what is a key-value (KV) cache? Give a complete, systems-level explanation that covers: ...

Software Engineering Fundamentals
227
1
1547 people solved
Jan 6, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Design an Agent Harness and Evaluation System

Design an Agent Harness and Evaluation System Design a harness and evaluation platform for a tool-using AI agent. The agent receives a user task, may ...

ML System Design
7
0
91 people solved
Apr 19, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer Locked

Filter Bad Human Annotations

This question evaluates expertise in data quality and annotation filtering for machine learning, including annotator reliability modeling, noisy-label...

Machine Learning
125
0
1384 people solved
Apr 3, 2026
OpenAI logo
OpenAI
Hard
Machine Learning Engineer

Derive Backpropagation for Matrix-Product Layers

Consider a neural-network block whose output is produced by multiplying a sequence of trainable weight matrices together, then applying the resulting ...

Machine Learning
51
0
594 people solved
Feb 5, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Mine Novel Images from Unlabeled Data

Design a machine learning system that mines novel or interesting images from a massive, unlabeled image corpus. The corpus is far too large for exhaus...

ML System Design
14
0
213 people solved
Apr 3, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Design First-Fit and Best-Fit Memory Allocation

Design First-Fit and Best-Fit Memory Allocation Design a simplified allocator over one contiguous arena of N bytes. It supports: - allocate(size, stra...

Software Engineering Fundamentals
5
0
56 people solved
Apr 19, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer

Defend a Research Direction and Experiment Design

You are interviewing for a research-focused Machine Learning Engineer role at a frontier AI lab. The onsite includes a collaboration / research-discus...

Machine Learning
30
0
202 people solved
Apr 13, 2026
OpenAI logo
OpenAI
Medium
Machine Learning Engineer Locked

Debug a Broken Transformer

This question evaluates proficiency in debugging and reconfiguring Transformer-based deep learning models, covering competencies in model internals (a...

Machine Learning
103
0
810 people solved
Mar 3, 2026
OpenAI logo
OpenAI
Hard
Machine Learning Engineer

Analyze matrix multiplication complexity

In an ML coding interview, you're handed a PyTorch file and asked a series of complexity questions about the operations in it. One of them: Given two ...

Software Engineering Fundamentals
75
0
528 people solved
Feb 11, 2026

Frequently Asked Questions

How difficult are OpenAI Machine Learning Engineer interview questions?
OpenAI Machine Learning Engineer interview questions are typically challenging and designed to measure both breadth and depth across software engineering and ML fundamentals. You should expect practical coding problems that test algorithmic thinking and code quality, as well as ML-focused questions that probe your understanding of model architectures, optimization, training stability, and evaluation. Senior roles add system-level design and deep technical dives into past work. Interviewers evaluate problem solving, clarity of thought, and trade-off reasoning rather than rote memorization, so preparation should emphasize applied skills and crisp explanations.
What is the typical OpenAI interview process and where do Machine Learning Engineer topics appear?
The OpenAI interview process usually begins with a resume review and a recruiter or hiring-manager conversation, followed by a skills-based assessment which may be a live coding screen or take-home project. Candidates who advance face a virtual onsite loop of multiple interviews that mix coding, ML-specific technical rounds, system-design discussions, and behavioral or mission-fit conversations. Machine learning topics show up in the technical screens and role-specific rounds as questions on architectures, training dynamics, distributed training and model debugging, and in a technical deep dive of a past project.
How much time should I allow to prepare for an OpenAI Machine Learning Engineer interview?
A sensible timeline for thorough preparation is four to eight weeks, depending on your starting point and the seniority of the role. Use the early weeks to refresh core ML concepts, practice coding problems focused on practical data-structure tasks, and review system-design patterns for training and serving models. Reserve later weeks for mock interviews, a polished technical deep dive presentation of a past project, and targeted safety/ethics reading relevant to OpenAI’s work. Note that OpenAI can sometimes expedite hiring for strong candidates, so be ready to compress preparation if the schedule accelerates.
What key subtopics should I prioritize when studying for an OpenAI Machine Learning Engineer role?
Prioritize subtopics that reflect both engineering and ML rigor: model architectures and training dynamics (optimization, regularization, and convergence issues), evaluation and metrics for model behavior, data preprocessing and feature engineering, distributed and efficient training, inference latency and serving, and debugging model failures. Also study system design for large-scale ML pipelines, monitoring and reliability, and safety/robustness considerations. Complement technical knowledge with clean coding practices and the ability to explain trade-offs and experimental design decisions clearly, since interviewers will probe both implementation skill and reasoning.
What standout tips and common pitfalls should I keep in mind when preparing for OpenAI Machine Learning Engineer interviews?
Focus on clear, structured explanations and on demonstrating pragmatic trade-offs; interviewers value reasoning as much as correct answers. Prepare a short, defensible technical deep dive of a project that highlights design choices, failure modes, and measurable impact. Practice coding with test-driven thinking and be ready to write readable, well-tested code during live exercises. Don’t ignore safety, ethics, and mission-fit questions—show awareness without overstating domain expertise. Common pitfalls include overcomplicating solutions, failing to communicate assumptions, and neglecting to discuss how you validated or monitored real systems.

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