OpenAI Software Engineer Interview Questions

OpenAI Software Engineer interview questions typically probe both classic engineering fundamentals and how you apply them in a research-driven, safety-conscious environment. What’s distinctive is the strong emphasis on mission alignment, clear technical communication, and the ability to reason about tradeoffs in complex ML systems; interviews commonly evaluate algorithmic problem solving, system design, code quality, and a technical deep dive into past projects. You should expect a mix of pair-coding or timed coding assessments, one or more domain-focused technical interviews, and behavioral discussions that assess collaboration, ownership, and ethical reasoning. For effective interview preparation, balance algorithm and data-structure practice with system-design thinking and a polished narrative about your projects. Familiarize yourself with OpenAI’s public research, blog posts, and the company’s charter so you can discuss how your work would fit the mission. Practice articulating design tradeoffs, writing clear, testable code under time pressure, and presenting a technical deep dive of a past project with measured outcomes. Recruiters often share format details and prep pointers, so use those to tailor your study and mock interviews.

174 Questions 1 Company08.11.2026
Showing 14 results
Role
OpenAI logo
OpenAI
Medium
Software Engineer

Merge overlapping time intervals efficiently

Given a list of closed intervals [start, end] with 0 <= start <= end, merge all intervals that overlap or touch and return a minimal set of non-overla...

Coding & Algorithms
15
1
205 people solved
Jul 31, 2025
OpenAI logo
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
OpenAI logo
OpenAI
Medium
Software Engineer Locked

Implement IPv4 and CIDR iterators

This question evaluates understanding of IPv4 addressing and CIDR notation, along with competency in binary/bitwise arithmetic, iterator construction,...

Coding & Algorithms
12
0
129 people solved
Jan 10, 2025
OpenAI logo
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
OpenAI logo
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
OpenAI logo
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
Easy
Software Engineer

Implement Chat Event Counter

Design an in-memory counter for chat activity. You need to implement a class with the following two methods: `text processEvent(userId: string, chatId...

Coding & Algorithms
2
0
24 people solved
Apr 10, 2026
OpenAI logo
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
OpenAI logo
OpenAI
Hard
Software Engineer Locked

Implement type AST and infer generics

This question evaluates a candidate's ability to design an abstract syntax tree representation and implement generic type inference for a small langua...

Coding & Algorithms
26
2
363 people solved
Feb 11, 2026
OpenAI logo
OpenAI
Medium
Software Engineer Locked

Implement an IPv4 Iterator

This question evaluates proficiency in IPv4 address representation and arithmetic, CIDR parsing, iterator API design for forward and backward traversa...

Coding & Algorithms
4
0
47 people solved
Jan 19, 2026
OpenAI logo
OpenAI
Medium
Software Engineer

Implement delimiter-free string codec

Design an encoder/decoder for a list of strings. - Implement two functions: - encode(strings: List[str]) -> str - decode(blob: str) -> List[str] -...

Coding & Algorithms
13
0
110 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
OpenAI logo
OpenAI
Medium
Software Engineer

Implement expiring credit ledger

Implement an expiring-credit ledger that supports out-of-order events. Expose three functions with the following semantics: - add_credit(id, amount, t...

Coding & Algorithms
25
0
250 people solved
Sep 6, 2025
OpenAI logo
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 Software Engineer Interview Prep
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Frequently Asked Questions

How difficult are OpenAI Software Engineer interview questions?
OpenAI Software Engineer interviews are generally rated as challenging and selective, combining algorithmic rigor with real-world engineering judgment. Candidates can expect medium-to-hard coding problems under time constraints, system design questions for scalability and reliability, and role-specific deep dives that probe architecture and implementation choices. Difficulty scales with level: entry-level roles emphasize data structures and clean code, mid-level roles add system and product tradeoffs, and senior roles demand architectural leadership and cross-team impact. Success hinges on clear reasoning, high-quality code, and the ability to explain tradeoffs rather than just producing a correct answer.
What is the typical process and where do Software Engineer topics appear in the interview loop?
The hiring process usually begins with a recruiter screen followed by one or more technical assessments that may include live pair coding, take-home projects, or timed coding tests. If you advance, the final stage commonly consists of a multi-hour interview loop with focused sessions such as coding, system design, and a technical deep dive into past projects, plus behavioral or values interviews. Software Engineer topics appear throughout: coding skills are evaluated in pair-programming and timed assessments; system design and distributed systems show up in architecture interviews; and the technical deep dive tests implementation detail and product impact.
How much time should I spend preparing and what does a reasonable timeline look like?
Preparation time depends on your baseline: engineers already comfortable with algorithms and systems might need four to six weeks of focused practice, while others should plan two to three months. Early weeks are best spent refreshing core data structures, algorithms, and coding fluency in the language you’ll use. Midway, shift to system design, distributed systems patterns, and practical performance considerations, while carving time for a polished project deep dive that highlights impact. In the final weeks, prioritize timed mock interviews and feedback cycles to improve clarity, speed, and the habit of explaining tradeoffs under pressure.
What key subtopics should I focus on for an OpenAI Software Engineer role?
Concentrate on solid mastery of algorithms and data structures, including graphs, trees, dynamic programming, and complexity reasoning. System design is critical: practice designing scalable services, model-serving pipelines, caching strategies, and data modeling with attention to latency, throughput, and reliability. Emphasize code quality, testing, and observability, and for roles touching model infra or research, review distributed training basics, performance profiling, and robustness considerations. Finally, expect evaluation on debugging, tradeoff analysis, and the ability to reason about safety, cost, and operational constraints in production environments.
What standout tips and common pitfalls should I know before interviewing?
Standout preparation includes practicing clear, structured communication: state assumptions, propose approaches, and iterate while explaining tradeoffs. Develop a concise technical deep dive for a past project that highlights design decisions, metrics, and lessons learned. During coding, write correct, well-tested code and prioritize clarity over cleverness. Common pitfalls include diving into micro-optimizations too early, failing to validate edge cases or invariants, neglecting operational concerns like monitoring and cost, and downplaying collaboration or safety tradeoffs. Demonstrating humility, curiosity, and alignment with mission-driven constraints often distinguishes successful candidates.

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