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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 661–690 of 1026 results
- NuroHardSoftware EngineerImplement a thread-safe periodic job scheduler
Implement a thread-safe periodic job scheduler evaluates engineering fundamentals, trade-offs, examples, pitfalls, and operational implications in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Software Engineering FundamentalsOnsite - OdeEasySoftware EngineerLive TDD Pairing: Grow a Multiset Class One Test at a Time
A live test-driven pairing exercise where you narrate test cases for a multiset (bag) class one behavior at a time while the interviewer writes the code, judged on test design, incremental thinking, and how you talk through implementation choices.
Software Engineering FundamentalsTechnical Screentddpair-programmingtesting - OdeEasySoftware EngineerTest-Driven Pair Programming: Grow a Java Set Class from Unit Tests
A test-driven pair-programming exercise in which you describe unit tests while the interviewer types, growing a Java set class one operation at a time with the simplest code that makes each test pass. It tests test-case design, incremental refactoring, clear verbal communication and how you would later expand the set.
Software Engineering FundamentalsTechnical Screen - OktaMediumSoftware EngineerBuild an Auth0-protected MCP server
This question evaluates proficiency in implementing JWT-based authentication and scope-based authorization for an HTTP service, covering token signature and claims validation, JWKS public-key verification, middleware integration, and propagation of identity information.
Software Engineering FundamentalsOnline Assessment - OnepayMediumSoftware EngineerDebug and Extend a Device Registry: Status Validation, Active Counts, Bulk Updates
A progressive coding exercise on a device registry: find the bug behind a failing test where a device's status must be allowed for its type, then add validated registration, per-type counts of active devices that omit zeros, and a bulk status update based on maintenance time and failure count. It tests code reading and business logic.
Software Engineering FundamentalsTechnical Screen - OpenAIMediumSoftware EngineerAt-Least-Once Job Queue with Timeouts, Retries, a Dead-Letter Queue and Dependencies
Implement an in-memory job queue with enqueue, reserve, pass, fail and a dead-letter queue, where reservations that outlive their timeout are redelivered for at-least-once delivery, then extend enqueue with job dependencies. It tests state-machine design, timeout tracking, retry accounting and dependency handling.
Software Engineering FundamentalsTechnical Screen - OpenAIHardSoftware EngineerBuild a Reliable Streaming Chat UI
This question evaluates understanding of real-time front-end architecture and state management in React, focusing on transient streaming state, concurrency control, UI consistency during tokenized updates, and the appropriate use of hooks such as useRef versus useState in the Software Engineering Fundamentals domain.
Software Engineering FundamentalsHR Screen - OpenAIMediumSoftware EngineerBuild a SaaS API-Credit Ledger With Expiring Grants and Late Events
Implement an API-credit ledger that grants, spends, and reports balances, where each grant expires and spending always draws from the soonest-expiring usable grant first, even when operations arrive out of timestamp order.
Software Engineering FundamentalsOnsitedata-structuresheapevent-ordering - OpenAIMediumSoftware EngineerClarify a Machine Topology Coding Task
Implement and formalize an API to analyze distributed accelerator interconnect topologies, separating summary metrics from component-level graph structures and validating topologies like rings, cliques, and lines.
Software Engineering FundamentalsTechnical Screengraph-algorithmsbfsapi-design - OpenAIMediumSoftware EngineerClarify and Design Social-Graph Milestones
Clarify ambiguous social-graph milestones before designing follow and unfollow operations, consistent snapshots, and user recommendations. The discussion tests directed-edge semantics, snapshot guarantees, recommendation-policy choices, exclusions, deterministic tie rules, scale assumptions, and contract-focused testing.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerContiguous Extent Allocator for a Storage Volume, Then O(log n)
Build an allocator that hands out contiguous runs of blocks on a fixed-size volume and takes them back with coalescing, first with a simple sorted list and then with logarithmic reserve and release. Tests splitting/merging logic, choosing indexes for size and neighbor lookups, and keeping them consistent.
Software Engineering FundamentalsTechnical Screenallocatordata-structuresbalanced-bst - OpenAIHardSoftware EngineerCount Events in a Trailing 15-Minute Window with a Fixed-Size Ring Buffer
Implement an event counter that returns how many events occurred in the trailing 15 minutes, using a fixed-size ring buffer of per-second buckets so memory stays bounded at any event rate. It tests circular buffers, stale-slot detection, window boundaries, late events and thread safety.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerCount Machines and Recover a Distributed Tree Topology
Implement a distributed tree discovery and aggregation protocol that counts reachable machines, recovers edges, handles network retries, detects unreachable subtrees, and validates tree invariants.
Software Engineering FundamentalsTechnical ScreenDistributed SystemsTreeGraph Traversal - OpenAIMediumSoftware EngineerDesign First-Fit and Best-Fit Memory Allocation
Design an in-memory heap allocator supporting first-fit and best-fit allocation, block splitting, adjacent free block coalescing, and safe handle validation to prevent stale or forged free operations.
Software Engineering FundamentalsTechnical ScreenMemory ManagementData StructuresLinked List - OpenAIMediumSoftware EngineerDesign a Time-Windowed GPU Credit Ledger
Design an in-memory credit ledger that manages time-windowed resource grants and consumptions with out-of-order event ingestion, deterministic allocation, and balance reconciliation.
Software Engineering FundamentalsTechnical ScreenData StructuresSimulationIntervals - OpenAIMediumSoftware EngineerDesign a social network with snapshots
This problem tests your ability to design a memory-efficient versioned graph structure that supports efficient edge retrieval at arbitrary points in time.
Software Engineering FundamentalsTechnical ScreenGraphData StructuresVersioning - OpenAIMediumSoftware EngineerDispatch Parcels to Delivery Drones That May Go Silent Mid-Flight
Build an in-process dispatcher that hands delivery parcels to drones, reclaims a parcel when its drone goes silent, rejects stale reports from a drone that already lost its parcel, and quarantines parcels that fail too many times.
Software Engineering FundamentalsTechnical Screenconcurrencystate-machinereliability - OpenAIHardSoftware EngineerDurable Session Cache: Byte Checkpoints, Segments, Thread Safety
A three-part exercise building a durable in-memory session cache: serialize entries to length-prefixed bytes and checkpoint them to disk, split the checkpoint into size-capped segments that reassemble by concatenation, then discuss making the class thread-safe. Tests byte-level encoding, exact round-tripping, and concurrency reasoning.
Software Engineering FundamentalsTechnical Screenserializationpersistenceconcurrency - OpenAIMediumSoftware EngineerExpiring GPU Credit Ledger with Out-of-Order Events and Point-in-Time Balance
A two-part coding exercise to build a GPU credit ledger with expiring grants, usage deducted earliest-expiration-first, out-of-order events and balance queries at any timestamp, then avoid replaying from time zero on every query. It tests event ordering, heap use, checkpointing and invalidation when late events arrive.
Software Engineering FundamentalsTechnical Screen - OpenAIHardSoftware EngineerExplain JS threading and useState vs useRef
This question evaluates understanding of JavaScript's execution model and concurrency mechanisms (including worker-based threading) along with React state-management semantics, specifically the behavioral differences between useState and useRef.
Software Engineering FundamentalsHR Screen - OpenAIHardSoftware EngineerFault-Tolerant Task Queue with Retries, a Dead-Letter Queue and Task Dependencies
Implement an in-memory fault-tolerant task queue with enqueue, reserve, complete and fail operations, retries up to a configurable attempt limit, and a dead-letter queue for tasks that keep failing. A second part adds dependencies between tasks, testing state-machine design, efficient readiness tracking and handling of failed dependencies.
Software Engineering FundamentalsTechnical Screen - OpenAIHardSoftware EngineerFault-Tolerant Task Queue with Retry Cooldowns, a Dead-Letter Queue and Dependencies
Implement an in-memory fault-tolerant task queue with enqueue, reserve, fail and a dead-letter queue, where each failed task waits out its own cooldown measured from the failure time and returns in its original enqueue order. A second part adds task dependencies, testing state modeling, efficient scheduling and careful edge-case handling.
Software Engineering FundamentalsTechnical Screen - 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 - 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 - OpenAIMediumSoftware EngineerImplement a Recoverable In-Memory Key-Value Store
This problem tests your understanding of durability, logging, and data persistence in an in-memory system.
Software Engineering FundamentalsTechnical ScreenSystemsConcurrencyPersistence
Nuro
Okta
OpenAI