OpenAI interview practice
Practice from 47 OpenAI-tagged public coding problems, organized only by the stage, topic, difficulty, and recency metadata FastPrep can verify. The broader public catalog also includes 13 system-design exercises, 1 project-coding exercise.
OA practice path
Build a timed implementation rhythm from prompt to edge cases. Problems are ranked by repeated public catalog sightings.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
OPOpenAI | Count Valid SequencesDynamic ProgrammingHash Table | Medium | 1 public reportLast reported Jan 2025 | Practice |
OPOpenAI | Count Matching Regions in Two Binary GridsMatrixGraph | Medium | 1 public reportLast reported Oct 2024 | Practice |
OPOpenAI | Maximize Wall HitsDynamic ProgrammingGreedy | Hard | 1 public reportLast reported Sep 2024 | Practice |
OPOpenAI | Largest Square Subgrid Under a Sum LimitMatrixPrefix Sum | Medium | 1 public reportLast reported Dec 2021 | Practice |
OPOpenAI | Backpropagation Through Sort and MedianArraySorting | Hard | 1 public reportLast reported Feb 2019 | Practice |
Phone practice path
Practice solving while explaining assumptions, tradeoffs, and complexity. Problems are ranked by repeated public catalog sightings.
35 OpenAI-tagged Phone Screen problems available.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
OPOpenAI | Versioned Social NetworkDesignHash Table | Hard | 11 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | GPU Credit LedgerDesignSimulation | Hard | 8 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Sparse Plant Infection SimulationSimulationHash Table | Hard | 6 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 1: Batch EntropyArrayMath | Easy | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 2: Numerically Stable EntropyArrayMath | Medium | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 3: Block-wise EntropyArrayMath | Medium | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 4: Stable Streaming EntropyArrayMath | Hard | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Plant Infection Simulation, Part 4: Death CountdownMatrixSimulation | Hard | 4 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Versioned Followers and FolloweesDesignGraph | Medium | 4 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Versioned Friend RecommendationsGraphBinary Search | Hard | 3 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Resumable List IteratorArrayDesign | Medium | 3 public reportsLast reported Jun 2026 | Practice |
OPOpenAI | Aggregate Machine TopologyTreeGraph | Medium | 2 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | In-Memory Key-Value Store SerializationHash TableString | Medium | 2 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Prefix Matrix Products and AutogradMatrixPrefix Sum | Hard | 2 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Memory AllocatorDesignIntervals | Medium | 2 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Grid Infection Spread Until StableMatrixSimulation | Medium | 2 public reportsLast reported May 2026 | Practice |
OPOpenAI | Grid Infection with Immune Cells Until StableMatrixSimulation | Medium | 2 public reportsLast reported May 2026 | Practice |
OPOpenAI | Dependency-Aware Agent Task SchedulerGraphTopological Sort | Medium | 1 public reportLast reported Aug 2026 | Practice |
OPOpenAI | Modal Lock and Fair Modal LockDesignSimulation | Hard | 1 public reportLast reported Aug 2026 | Practice |
OPOpenAI | One-Nearest-Neighbor ClassificationArrayMatrix | Easy | 1 public reportLast reported Aug 2026 | Practice |
Onsite practice path
Practice complete solutions and defend the choices behind them. Problems are ranked by repeated public catalog sightings.
| Company | Problem | Difficulty | Public evidence | Action |
|---|---|---|---|---|
OPOpenAI | Versioned Social NetworkDesignHash Table | Hard | 11 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | GPU Credit LedgerDesignSimulation | Hard | 8 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Sparse Plant Infection SimulationSimulationHash Table | Hard | 6 public reportsLast reported Aug 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 1: Batch EntropyArrayMath | Easy | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 2: Numerically Stable EntropyArrayMath | Medium | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 3: Block-wise EntropyArrayMath | Medium | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Streaming Entropy, Part 4: Stable Streaming EntropyArrayMath | Hard | 5 public reportsLast reported Jul 2026 | Practice |
OPOpenAI | Durable Work Queue OperationsHash TableQueue | Hard | 1 public reportLast reported Aug 2026 | Practice |
OPOpenAI | 15-Minute Chat Session TrackerHash TableSliding Window | Hard | 1 public reportLast reported Jul 2026 | Practice |
OPOpenAI | Tensor-Parallel MLP GradientsArrayMatrix | Hard | 1 public reportLast reported Jul 2026 | Practice |
OPOpenAI | Message Event AggregationHash TableSliding Window | Medium | 1 public reportLast reported Jul 2026 | Practice |
OPOpenAI | DSA Round: Maximum Score Grid PathDynamic ProgrammingMatrix | Hard | 1 public reportLast reported May 2026 | Practice |
OPOpenAI | Convert an IPv4 Range to Minimal CIDR BlocksStringBit Manipulation | Medium | 1 public reportLast reported Oct 2025 | Practice |
OPOpenAI | Toy Language Generic Return-Type InferenceStringParsing | Hard | 1 public reportLast reported Mar 2025 | Practice |
01 · Stage workflow
The current public inventory is phone-screen heavy and also contains design practice, so rehearse clear reasoning aloud alongside implementation and architecture work. Your invitation and recruiter guidance remain the source of truth.
Use the timing and format in your invitation as the source of truth. In practice, work without interruptions, budget time to read constraints, and reserve a final review window for boundary cases.
Treat the problem as a conversation. Clarify the contract, describe the approach before implementation, and keep narrating meaningful decisions while you code and test.
Use the catalog's onsite labels as practice context, not as a promise about a specific loop. Focus on collaborative problem solving: compare approaches, implement cleanly, and explain how the solution behaves at scale.
02 · Broader technical practice
These public OpenAI-tagged exercises cover additional technical formats. They are included only when a verified catalog record and a crawlable practice page both exist.
Design a demand-response control plane that detects overload, protects critical loads, requests voluntary reductions, and reconciles unreliable device evidence.
Open practiceDesign a platform that ingests generating-unit telemetry and runs durable distributed analyses for plant operators.
Open practiceDesign a global platform for acquiring games, maintaining user libraries, delivering large builds and patches, authorizing launches, and processing refunds.
Open practiceDesign matchmaking, authoritative game sessions, routing, and chess-clock timeout behavior for an online chess service that can grow from a new product.
Open practiceDesign durable upload, authorized download, content-addressed byte reuse, and reference-safe deletion for large opaque objects.
Open practiceDesign a Sora-like platform that durably schedules long-running video-generation jobs, survives infrastructure failures, and publishes complete video artifacts.
Open practiceDesign a payment lifecycle service that moves funds through hold, charge, and settlement with idempotency and reconciliation.
Open practiceDesign a highly available text-generation service that streams model responses, scales scarce inference capacity, recovers from failures, and exposes useful operational metrics.
Open practiceDesign a correct payment-recording and nightly reconciliation system for in-store merchants and their acquiring banks.
Open practiceDesign a distributed search service that solves crossword grids while preventing workers from exploring the same logical search state.
Open practiceDesign a reliable payment path that turns an order into one captured charge and reconciles uncertain provider outcomes.
Open practiceDesign a reusable platform that measures agent quality from online feedback and reproducible offline evaluations without coupling teams to one agent implementation.
Open practiceDesign a two-region control plane that plans and applies versioned infrastructure changes safely across unreliable provider APIs.
Open practiceDebug a multi-rule Django rate limiter so sliding windows stay independent, atomic, bounded, and safe under concurrent requests.
Open practice03 · Evidence boundary
It means practicing transferable implementation, testing, and technical reasoning with public catalog assets FastPrep tags to OpenAI. It does not mean FastPrep has access to the company's assessments or any private interview bank.
Repeated public sightings and last-reported dates can help you prioritize practice, but they cannot predict the questions, format, or platform in a specific interview.
04 · Plain answers
This page owns technical-practice intent for OpenAI. Hiring activity, timelines, and market signals remain on the separate hiring-insights page.
Yes, when the public catalog supports it. This page currently links 13 system-design exercises, 0 low-level-design exercises, and 1 project-coding exercise tagged to OpenAI. Empty formats are omitted rather than padded with generic recommendations.
No. FastPrep is an independent interview-preparation product and is not affiliated with OpenAI. The page uses FastPrep's public practice catalog and does not claim official, private, leaked, or proprietary employer questions.
Stage labels come from FastPrep's public problem metadata. A problem can carry more than one reported stage, and hiring processes can change by role, level, location, and date. Treat the labels as preparation context, not a guarantee.
Start with the stage named in your invitation or recruiter message. If no stage is known, use the largest available set to build general problem-solving fluency, then rehearse explanation and testing separately.
No. Public catalog counts, stage tags, and last-reported dates can help prioritize practice, but they cannot predict a specific interview's questions, sequence, timing, or platform.
Your next stage, made concrete
Start with the stage named in your invitation, then use public evidence as context—not as a promise of what you will be asked.
Open the practice set