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Software Engineer Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
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Showing 1651–1680 of 2336 results
- OpenAIMediumSoftware EngineerDesign an Asynchronous Text-to-Video Generation Service
This question tests the ability to design a high-latency, asynchronous job-processing pipeline with a focus on fault tolerance, job state management, and reliable resource handling.
System DesignOnsiteAsync ProcessingScalabilityJob Queues - OpenAIHardSoftware EngineerDesign an Online Chess Platform: Elo Matchmaking, WebSocket Moves, Game Clocks
Design an online chess platform: match players of similar Elo rating quickly, deliver moves in real time over WebSocket connections, and enforce fair game clocks despite network latency and disconnections. It tests matchmaking, stateful real-time architecture, server-authoritative timing and failover.
System DesignOnsite - OpenAIMediumSoftware EngineerDesign an Online Chess Service from Launch to Scale
This problem tests the ability to design a real-time, stateful gaming system, focusing on concurrency control, low-latency communication, and fault tolerance.
System DesignOnsiteReal-timeConcurrencyWebSockets - OpenAIHardSoftware EngineerDesign an Online Multiplayer Chess Service with Real-Time Moves
Design an online chess service where two remote players play live games, every move is validated and delivered to the opponent immediately, and results are recorded. It tests authoritative game state, real-time transport, fair clocks, move ordering, recovery of games in progress after failures, and scaling to many concurrent games and spectators.
System DesignOnsite - OpenAIHardSoftware EngineerDesign an SSH-Based Cloud Development Environment
This question tests your ability to design a distributed system that manages stateful, long-running compute resources while ensuring isolation, high availability, and secure remote access.
System DesignOnsiteDistributed SystemsCloud InfrastructureSecurity - OpenAIMediumSoftware EngineerDesign coffee-shop card payments with tips and nightly batch settlement at scale
Design a card payment system for coffee shops where purchases are authorized at the counter, tips are added afterwards, and transactions settle in a nightly batch. The discussion centers on scaling nightly settlement, along with idempotent APIs, failure handling and reconciliation against processor reports.
System DesignOnsite - OpenAIMediumSoftware EngineerDesign power grid device monitoring over an unreliable public internet
Design a monitoring system for power grid field devices that report their status over an unreliable public internet. It tests store-and-forward reporting, idempotent ingestion of late and duplicate data, telling silent devices from failed ones, alerting, and security for critical infrastructure.
System DesignOnsite - OpenAIMediumSoftware EngineerDesign webhook, POI, chat, CI/CD, payments
This question evaluates proficiency in distributed system design, covering scalability, availability, durability, data modeling, geospatial indexing, event-driven delivery, API design, fault tolerance, security, and operational monitoring for high-throughput backend services.
System DesignOnsite - OpenAIHardSoftware EngineerExplain your perspective on AI safety
An OpenAI software engineer onsite behavioral question asking you to define AI safety in practical product terms, triage near-term versus long-term risks, and assess AI's effect on human work, the economy, and society. The answer must then connect those views to concrete engineering practice — threat modeling, guardrails, evals and red-teaming, phased rollout, and incident response. It also tests whether you can balance responsible deployment against shipping speed in both directions.
Behavioral & LeadershipOnsite - OpenAIHardSoftware EngineerFault-Tolerant Work Queue with Leases, Fencing Tokens and DAG Task Dependencies
Implement a fault-tolerant work queue in which workers claim tasks under expiring leases, crashed workers' tasks are reassigned, and late reports from stale workers are rejected, then add DAG dependencies with cycle detection. It tests leases, fencing tokens, topological release and delivery semantics.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerFind a Hidden Number When Each Comparison Answer Arrives One Call Late
Find a hidden integer from 1 to n using a comparison API whose answers arrive one call late: each call submits a new guess but returns the result for the previous one. Build a correct search first, then reduce the worst-case number of calls. It tests binary search under delayed feedback and worst-case analysis.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerFollow Graph with Cheap Snapshots and Top-K Follow Recommendations
Build a one-directional follow graph that supports cheap snapshots and queries against past snapshots, then recommend the top k accounts a user should follow. It tests versioned data structures, snapshot semantics, two-hop graph traversal, heap-based top-k selection and scaling to highly connected accounts.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerGPU Credit Ledger with Expiring Grants, Out-of-Order Operations and Fast Balances
Implement a GPU credit ledger with expiring grants, subtractions that spend the soonest-expiring credits first, and balance queries, where operations can arrive out of timestamp order. Then avoid recomputing from time zero on every query. It tests event replay, priority queues and checkpoint invalidation.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerGPU Credit Ledger: Spend Earliest-Expiring Credits First, Stop on Overdraft
A coding and design question about an in-memory GPU credit ledger that grants expiring credits, charges usage against the credit that expires soonest, and returns no balance once any charge overdraws the account. It tests data structure choice, expiry and boundary conventions, and optimizing the ledger for a very large number of credit changes.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerGame Telemetry Windows: Match Counts, Live Sessions, Late Events
Build an in-memory service that counts per-match actions inside a global 10-minute window, tracks each player's live client sessions from heartbeats and logouts, and stays correct when events arrive late. Tests bounded-memory eviction, amortized analysis, lazy deletion and exact window semantics.
Software Engineering FundamentalsOnsitesliding-windowheapqueue - OpenAIHardSoftware EngineerImplement Disease and Friend Snapshot Models
This question evaluates skills in graph-based modeling and temporal state simulation as well as the design and implementation of snapshot-capable directed graph data structures, covering competencies in propagation and state transitions (including immunity, recovery, and death), efficient snapshotting, querying, ranking, and diffing of follow relationships. It is commonly asked to assess algorithmic reasoning, correctness under edge cases, and complexity-aware implementation; the problem belongs to the Coding & Algorithms domain and tests both conceptual understanding of dynamic graph behavior and practical application-level implementation of data structures and immutable snapshots.
Coding & AlgorithmsOnsite - OpenAIHardSoftware EngineerImplement IP Address Arithmetic
Implement parsing, binary representation, arithmetic offsets, and canonical formatting for both IPv4 and IPv6 addresses and CIDR subnets.
Coding & AlgorithmsOnsitebit-manipulationstring-parsingnetworking - OpenAIMediumSoftware EngineerImplement a GPU credit ledger with expiring grants and out-of-order operations
Implement a GPU credit ledger with grant, subtract and get-balance operations, where grants expire and spending draws from the soonest-expiring grant first. Operations can arrive out of timestamp order, and a follow-up asks how to avoid replaying the whole history from time zero on every query in production.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerImplement a Set with Readable Snapshots
Design and implement a versioned set data structure that supports membership modifications, instant snapshotting, and historical point-in-time queries efficiently.
Software Engineering FundamentalsOnsiteData StructuresDesignBinary Search - OpenAIMediumSoftware EngineerImplement a Simple Memory Allocator
This question evaluates low-level memory management and allocator design skills, including block header layout, free-list/data-structure choices, pointer arithmetic, fragmentation concepts, and analysis of time/space complexity.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerImplement an IPv4 Iterator
This problem tests your ability to handle IPv4 address arithmetic, bitwise operations, and the implementation of a stateful iterator that supports bidirectional traversal and range generation from CIDR notation.
Coding & AlgorithmsOnsiteBit ManipulationIterator PatternNetworking - OpenAIHardSoftware EngineerImplement an in-memory SQL-like table
This question evaluates implementation skills for an in-memory SQL-like table, focusing on data modeling with nested key-value structures, string handling, efficient lookups, and lexicographic sorting with tie-breaking.
Coding & AlgorithmsOnsite - OpenAIHardSoftware EngineerIn-Memory Key-Value Store with Crash Recovery from a Log and Concurrent Access
Implement an in-memory key-value store, make it recover from a log file after a crash, including a half-written final record, and make it correct and fast under many concurrent threads. It tests write-ahead logging, crash consistency, compaction, and lock design with group commit.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerIndexed Vector as a Linked List with Checkpoints Every k Nodes
Implement an indexed dynamic sequence of strings, in the sense of an array list, that supports inserting at a position and reading by position. Starting from a plain singly linked list, build a linked list with a checkpoint every k nodes so reads cost O(k), and keep the checkpoints correct as insertions shift positions.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerLeftmost-Fit Memory Allocator: Allocate Consecutive Units and Free by Owner
Simulate a memory allocator over n units: each allocation takes the leftmost run of consecutive free units for an owner, and each free releases all of that owner's units. Return the result of every operation. It tests interval bookkeeping and logarithmic-time search for free runs at up to 100,000 operations.
Coding & AlgorithmsOnsite - OpenAIHardSoftware EngineerLeftmost-Fit Theater Row Booking With Bulk Cancellation by Group
Simulate booking a single theater row of n seats, where each booking takes the leftmost block of consecutive free seats for a group and a cancellation releases every seat that group currently holds anywhere in the row. Tests augmented-interval bookkeeping and logarithmic-time search for the best free run.
Coding & AlgorithmsOnsitesegment-treeintervalssimulation - OpenAIHardSoftware EngineerModel particle hits on a screen
This question evaluates geometric reasoning and probability theory skills, specifically transformation of random variables and derivation of CDF/PDF from angular sampling, together with practical competence in Monte Carlo simulation and interpretation of numerical and visualization artifacts; domain: Software Engineering Fundamentals.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerMonitor Devices Over an Unreliable Network
Design an edge-to-cloud device monitoring system that accurately tracks device health and liveness across flaky, high-latency networks without falsely reporting absolute state.
System DesignOnsitesystem-designdistributed-systemsiot - OpenAIHardSoftware EngineerPlant Infection Grid Simulation: Days to Stabilize, Immune Plants, Expiring Immunity
A progressive grid simulation: infection spreads daily between adjacent plants, and you compute how many days the garden takes to stabilize, then add permanently immune plants and immunity that expires after a countdown. It tests multi-source breadth-first search, Dijkstra-style waiting times and precise day counting.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerProject Deep Dive: Proving Technical Depth and Cross-Team Alignment
A behavioral project deep-dive question in which you present a past project while the interviewer asks how you aligned with other functional teams and with engineers on your own team, and repeatedly presses on where the technical depth lies. It tests structured storytelling, clear ownership, evidence-backed decisions and composure under challenge.
Behavioral & LeadershipOnsite
OpenAI