OpenAI Interview Questions

OpenAI Interview Questions

Practice 274 real OpenAI interview questions for 2026 — real interview questions drawn from actual interviews with detailed solutions. OpenAI interview questions on this page span Coding & Algorithms, System Design, ML System Design, Machine Learning, and Data Manipulation (SQL/Python) and cover roles like Software Engineer, Machine Learning Engineer, Data Scientist, Android Engineer, and Frontend Engineer. For interview preparation expect a focus on production ML systems, scalable services, numerical correctness, experimental design, and communication: interviewers evaluate architecture decisions, tradeoffs, measurable impact, and the ability to ship robust systems under uncertainty. The loop runs stage-by-stage: a recruiter screen, a technical phone screen (coding or design), a virtual onsite with focused rounds (practical coding, system and ML design, model/debug deep dives, and behavioral/mission-fit), then team match and offer; typical timeline is about 4–8 weeks and difficulty is high. Practical coding leans toward real-world engineering problems rather than pure LeetCode puzzles. Software-engineer themes include consistent-hashing sharding, GPU job scheduling for text-to-video, payment systems with exactly-once semantics, and video orchestration. ML tracks emphasize resumable iterators and checkpoint/restore, streaming-entropy numerical stability, 1-NN implementations and debugging model backprop; data science focuses on churn, free-trial A/B tests, and SQL retention analysis. Use project deep-dives and worked examples when you prep.

274 Questions 1 Company08.01.2026
Showing 20 results
Role
OpenAI logo
OpenAI
Medium
Software Engineer

Implement persistent key-value store

Question Design and implement an in-memory key-value store supporting set(key, value), get(key), shutdown() that flushes all data as bytes to a medium...

Coding & Algorithms
22
0
297 people solved
Aug 4, 2025
OpenAI logo
OpenAI
Medium
Data Scientist

Design Schema and Logic for Subscription Event Tracking

user_subscription_events +----------+-------------+---------------------+-----------+---------+ | user_id | event_type | event_time | plan_...

Data Manipulation (SQL/Python)
71
0
159 people solved
Jul 12, 2025
OpenAI logo
OpenAI
Medium
Software Engineer

Implement map serialization and deserialization

You are given an in-memory map (dictionary) from strings to strings. Implement two functions: - string serialize(map<string, string> m) - map<string, ...

Coding & Algorithms
78
0
615 people solved
Dec 1, 2025
OpenAI logo
OpenAI
Hard
Software Engineer Locked

Design a team chat system

This question evaluates expertise in large-scale system design and distributed systems, focusing on real-time messaging, data modeling for users and c...

System Design
5
0
60 people solved
Oct 31, 2025
OpenAI logo
OpenAI
Medium
Software Engineer

Design a parser for a hypothetical language

You are given a set of syntax rules for a hypothetical programming language written in BNF/EBNF. Design data structures and algorithms that: ( 1) pars...

Coding & Algorithms
50
0
424 people solved
Sep 6, 2025
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OpenAI
Medium
Software Engineer

Implement KV store and plan type conversions

Part 1 — Versioned key-value store: Implement a data structure with set(key, value, t) and get_at(key, t) that returns the value for key whose timesta...

Coding & Algorithms
48
0
371 people solved
Sep 6, 2025
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OpenAI
Medium
Software Engineer

Optimize C++ Performance with Provided Concurrency

Given a C++ codebase where threading components (threads, work queues, and synchronization primitives) are already provided, profile and optimize the ...

Coding & Algorithms
10
0
167 people solved
Sep 6, 2025
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OpenAI
Medium
Software Engineer

Implement an expiring GPU-credit manager

Implement an expiring GPU-credit manager for a cloud provider. Each user receives credit grants with an amount and an expiration timestamp. Support: (...

Coding & Algorithms
54
0
478 people solved
Sep 6, 2025
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OpenAI
Medium
Software Engineer Locked

Design an online real-time chess game

Design a real-time online chess service with WebSockets, matchmaking, server-authoritative game state and clocks, durable event storage, reconnect, sh...

System Design
26
0
185 people solved
Jan 10, 2025
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OpenAI
Medium
Software Engineer

Merge overlapping intervals

Question LeetCode 56. Merge Intervals – Given a collection of intervals, merge all overlapping intervals into one and return an array of the non-overl...

Coding & Algorithms
23
0
218 people solved
Aug 4, 2025
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OpenAI
Medium
Data Scientist

Identify Bugs in Python Script for User Assignment

Scenario A simple Python script assigns users to experiment groups and triggers the free-trial offer. Question Inspect the script and list any bugs or...

Coding & Algorithms
27
0
86 people solved
Aug 4, 2025
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OpenAI
Medium
Software Engineer

Implement in-memory DB querying

Question Implement an in-memory database that supports: 1. Querying the whole table and returning only selected columns (projection). 2. Adding WHERE ...

Coding & Algorithms
191
1
663 people solved
Jul 29, 2025
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OpenAI
Medium
Software Engineer

Implement an expiring GPU credits ledger

Implement an expiring GPU credits ledger for multiple users with three operations: 1) add_credit(user_id, amount, expiry_time): add a lot of credits t...

Coding & Algorithms
51
0
422 people solved
Jul 27, 2025
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OpenAI
Medium
Software Engineer Locked

Implement A Contiguous Memory Allocator With Free-Block Coalescing

Review a contiguous memory allocator coding prompt with malloc, free, first-fit allocation, block coalescing, and a best-fit follow-up. The interview ...

Coding & Algorithms
22
1
165 people solved
Jun 5, 2026
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OpenAI
Medium
Software Engineer Locked

Compute Plant Infection Time

This question evaluates a candidate's understanding of graph traversal and grid-based state propagation, including concepts like breadth-first search,...

Coding & Algorithms
3
0
33 people solved
May 24, 2026
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OpenAI
Hard
Machine Learning Engineer Locked

Simulate Infection Spread on a Grid

This question evaluates the ability to implement and reason about discrete-time, grid-based simulations with multi-state cells and neighbor-dependent ...

Coding & Algorithms
7
0
78 people solved
May 11, 2026
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OpenAI
Medium
Software Engineer Locked

Build a File-Backed Key-Value Store

This question evaluates a candidate's understanding of persistent key-value storage, in-memory versus on-disk state management, serialization/deserial...

Coding & Algorithms
6
0
63 people solved
Apr 11, 2026
OpenAI logo
OpenAI
Hard
Machine Learning Engineer

Simulate Plant Infection With Controlled Burning

You are given an R by C grid of plants. Each plant is initially healthy, infected, recovered, or dead. A plant has up to four orthogonal neighbors. De...

Coding & Algorithms
2
0
9 people solved
Apr 2, 2026
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OpenAI
Medium
Software Engineer Locked

Minimize deaths in spreading plant infection

This question evaluates a candidate's ability to model and simulate dynamic grid processes, reason about infection propagation and delayed state chang...

Coding & Algorithms
100
0
1051 people solved
Apr 1, 2026
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OpenAI
Easy
Software Engineer

Design a Versioned Social Follow Graph with Friend Recommendations

Design a Versioned Social Follow Graph with Friend Recommendations Build an in-memory service that maintains a directed follow graph between users and...

Coding & Algorithms
1
1
4 people solved
Mar 16, 2026

Frequently Asked Questions

How difficult are OpenAI interview questions for software and ML roles in 2026?
OpenAI interviews in 2026 are challenging but not purely puzzle-driven: they reward practical engineering, systems thinking, and domain depth. Expect coding rounds that favor real-world tasks (reading and modifying components, debugging, performance-minded implementations) over contrived LeetCode riddles, plus heavy system and ML design for senior roles. Difficulty varies by track: Software Engineer interviews emphasize scalable distributed systems and orchestration; Machine Learning and Research tracks dig deeper into math, experiment design, and paper-level reasoning. Overall the loop is selective; prepare for multi-hour virtual onsites and high bar on correctness, clarity, and tradeoff justification.
What is the OpenAI interview process stage by stage and where do different question types appear?
The process typically starts with a recruiter or sourcer screen (30 minutes) covering fit and logistics, then a technical phone screen or hiring manager call that mixes coding and role-specific questions. Many loops include a paid or take-home exercise in applied roles, then a virtual onsite of four to six rounds: coding/debugging, system or ML systems design, a technical deep dive on your past work, and behavioral/mission-alignment conversations, followed by team-match interviews. Coding and Algorithms and Data Manipulation show up in early screens and onsite coding rounds; System Design and ML System Design dominate senior SWE and MLE rounds; Data Scientist rounds focus more on SQL, experiments, and A/B analysis.
How should I schedule my preparation and what timeline is realistic before interviewing at OpenAI?
Plan a 4–8 week preparation block aligned to the role. Weeks 1–2: solidify fundamentals—data structures, Python or chosen language fluency, and SQL skills with joins, windows, and CTEs. Weeks 3–4: practice role-specific system problems and ML fundamentals—distributed systems, caching, consistency, and experiment design. Weeks 5–6: run mock onsites, do timed coding, and prepare technical deep dives (projects, papers, metrics). Final 1–2 weeks: polish behavioral stories, team-fit pitch, and revisit tricky system/ML topics like checkpointing, numerical stability, and orchestration. Allow extra time if you must rebuild ML coding from scratch or reproduce papers.
What specific subtopics and problem types recur for OpenAI roles (coding, system design, ML, and data)?
For Software Engineers expect distributed-systems themes such as consistent hashing rings with virtual nodes, GPU job schedulers for text-to-video workloads, exactly-once payment processing, versioned social follow graphs, and video generation orchestration. Machine Learning Engineers see resumable iterators with checkpoint/restore, streaming entropy and numerical stability, 1-NN implementations and matrix gradient tricks, debugging MiniGPT-style training, mining novel images, and noisy-annotator strategies. Data Scientists focus on SQL for repeat churn, free-month promotion A/B tests, signup/retention lift calculations, and experiment measurement. Mobile and frontend roles weight architecture (MVVM, Compose) and model-usage quotas.
What are standout preparation tips and common pitfalls to avoid for OpenAI interviews?
Emphasize production-ready thinking: write clear, testable code, explain failure modes, and design for observability and reproducibility. For ML/research tracks, be ready to discuss papers, experimental design, statistical power, and how you'd debug and reproduce training runs. Avoid over-optimizing for abstract puzzle tactics; interviewers want debugging instincts, tradeoff reasoning, and a path to shipable systems. Common pitfalls include ignoring edge cases (concurrency, exactly-once semantics), skimming data-quality implications in experiments, failing to justify metric choices, and not framing past work in terms of tradeoffs and measurable impact during technical deep dives and team-match conversations.

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