OpenAI interview notes, page 1 of 67

Mid-sized

Most of these OpenAI write-ups come from Software Engineers (460), then Machine Learning Engineers (137) and Backend Engineers (23). The most reported rounds are the technical phone screen (335), the system design round (229), the onsite coding round (32) and the behavioral / leadership round (22).

667 interview notes · updated Jul 2026

OpenAI·Data Scientist·Technical Phone Screen

Apr 2024

Data Scientist interview at OpenAI focused on event-level data modeling for subscription systems. The core problem was messier than it looked on the surface, mostly because of the re-signup edge cases that trip people up if they're not careful about how they reconstruct state from raw events.

Design an event-level schema for subscription data that can accurately reconstruct a user's subscription status on any given date, including cases where a user signs up, cancels, and signs up again.

“I went straight to the obvious schema (user_id, timestamp, event_type, plan_type) and felt good about it.”

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OpenAI·Software Engineer·Recruiter / HR Screen

Apr 2026

Interviewed for a software engineer role at OpenAI and got hit with the classic 'why us specifically' question. Not a technical round, more of a fit and motivation screen.

Why do you want to work at OpenAI specifically, rather than any other AI company?

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

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OpenAI·Software Engineer·Onsite - Cross-functional / Panel

Apr 2026

Cross-functional round at OpenAI for a software engineer role. Three behavioral questions, all focused on how you handle things going sideways with projects or people. Nothing too surprising but the PM conflict one had a bit of an edge to it.

Tell me about a time a project you were working on got delayed. What happened and how did you handle it?
Describe a situation where you had a conflict with a product manager. How did you navigate it?
What's the largest project you've personally driven forward? Walk me through your role in it.

“Pretty standard but I fumbled the landing a bit.”

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OpenAI·Software Engineer·Onsite - System Design / Architecture

Apr 2026

System design round at OpenAI for a software engineer role. The whole session was basically one giant payment system question that kept branching into more and more subsystems. Walked out feeling like I'd covered maybe 60% of what they actually wanted.

Design a payment system end-to-end, covering initiation, authorization, capture, refunds, idempotency, ledger modeling, reconciliation with external processors, retry logic, partial failure handling, fraud detection hooks, observability, and consistency guarantees.

“This is a monster of a question and I did not pace myself well.”

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OpenAI·Software Engineer·Technical Phone Screen

Apr 2026

Got a coding screen for a Software Engineer role at OpenAI and the question was about IP address iteration. Niche enough that I had to think carefully about the 32-bit integer representation before writing a single line.

Design a class that iterates over IPv4 addresses in order. Given a starting IP and either a count or an end IP, implement a next() method that returns the next address as a string and handles wrap-around at the 32-bit boundary without storing all addresses in memory.

“The memory constraint is what makes this interesting.”

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OpenAI·Machine Learning Engineer·Technical Phone Screen

Apr 2026

Interviewed for an ML engineer role at OpenAI and got a deep reinforcement learning question that I thought I was ready for. Turns out knowing the theory and being able to explain it clearly under pressure are very different things.

Can you explain how deep reinforcement learning works?

“I started with the basic reward-agent-environment loop which was fine, but then I kind of rambled when trying to connect it to the deep learning side.”

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OpenAI·Software Engineer·Onsite - System Design / Architecture

Apr 2026

System design round at OpenAI for a software engineer role. The whole session was basically one big question about CI/CD infrastructure, which sounds narrow but went surprisingly deep once they started asking follow-ups.

Design a CI/CD system that handles building, testing, and deploying code changes across many repos and concurrent jobs. Cover how jobs get triggered, the pipeline execution model, build agents, artifact storage, secret management, retries, observability, and scaling.

“This one sprawls fast.”

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OpenAI·Software Engineer·Technical Phone Screen

Apr 2026

OpenAI technical phone screen for a software engineering role, one coding question focused on iterator design. Pretty niche problem, not your typical LeetCode grind.

You're given an IPv4 iterator class with a next() method that returns IP addresses sequentially as strings with correct 32-bit wrap-around. Implement a prev() method for backward iteration, handling the lower address boundary and ensuring prev() followed by next() returns to the same position.

“This one tripped me up more than it should have.”

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OpenAI·Software Engineer·Technical Phone Screen

Apr 2026

OpenAI SWE interview with a distributed systems coding problem that looked like a graph traversal question on the surface but was actually about designing a message-passing protocol from scratch. Trickier than I expected going in.

Given a root node and an async API sendAsyncMessage(nodeId, message), implement receiveMessage(fromNodeId, message) so that the network can count its total number of nodes. You can't access node children directly, only communicate via the async messaging API.

“The DFS framing is a bit of a red herring.”

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OpenAI·Software Engineer·Technical Phone Screen

Apr 2026

OpenAI SWE interview, project deep dive round that ran about 45 minutes. The interviewer clearly wanted to talk about the hard stuff, not the easy wins.

Walk me through a technically challenging project you've worked on.

“The interviewer steered away from anything that sounded routine pretty fast.”

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