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Software Engineering Fundamentals 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 391–420 of 1208 results
- DisneyEasySoftware EngineerHow would you run a mentoring-focused code review?
This question evaluates mentoring-focused code review competencies, including code quality and maintainability analysis, frontend architecture (React/TypeScript), testing strategy, accessibility and security awareness, plus written and interpersonal feedback skills.
Software Engineering FundamentalsOnsite - DisneyMediumSoftware EngineerImplement a Set Data Structure with a Resizable Array, Then Improve It with Hashing
Tests low-level data structure design by implementing a set from scratch using an array-backed hash table, focusing on collision resolution, dynamic resizing, load factor management, and amortized complexity.
Software Engineering FundamentalsTechnical ScreenData StructuresHash TableArrays - DisneyEasyData EngineerPrompting an LLM to Migrate a Java Codebase to Python and Clean a Large Database
Explain how you would prompt a large language model to migrate a Java codebase to Python and to help clean a database with tens of thousands of rows. It tests prompt design, verification of generated code and data fixes, data quality measurement, security of AI-assisted work and the handling of sensitive data.
Software Engineering FundamentalsOnsite - DisneyMediumSoftware EngineerThread-Safe Buffered Batch Writer for Streaming Records into a Database
Design and implement a thread-safe batch buffer that collects streaming records from multiple producer threads and flushes them to a database using batch inserts based on size, timeout, or shutdown triggers.
Software Engineering FundamentalsTechnical ScreenConcurrencyMultithreadingData Structures - DocuSignEasySoftware EngineerDesign a JSON Schema Validator
Design and implement a modular JSON schema validator that verifies data against structural schemas, supporting primitive types, nested objects, arrays, regex patterns, numeric ranges, and strict field controls.
Software Engineering FundamentalsOnsiterecursionoopdesign - DoorDashMediumSoftware EngineerBootstrap Service: Aggregate Downstream Services and Return the Right HTTP Status
Implement a bootstrap service that calls several independent downstream services concurrently, aggregates their data into one response for a client app, and returns an HTTP status code that reflects partial or total failure. It tests concurrent calls, timeouts, per-section error reporting, and mapping downstream failures to client-facing status codes.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerBuild Resilient Aggregation and Debug Routing
This question evaluates skills in building resilient API aggregation, fault-tolerant retry handling and test coverage for transient failures, as well as debugging and improving load-balancer routing policies including adding round-robin distribution and reasoning about consistent hashing.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerBuild Two Interacting Services That Carry Out a Realistic Refund Flow
A senior coding exercise, with an AI assistant allowed, to build two cooperating services that carry out a refund end to end. It tests service boundaries, a refund state machine, idempotent retries, handling of declines and timeouts, and a runnable simulation of realistic refund scenarios.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerBuild a Delivery Payout Calculation API
Build a payout endpoint that retrieves delivery activity and accrues 30 cents per minute for each concurrent order. The solution covers interval sweeps, malformed events, exact money, day boundaries, final rounding, upstream timeouts, retry limits, caching, and layered tests.
Software Engineering FundamentalsTechnical Screen - DoorDashMediumSoftware EngineerBuild a Resilient Bootstrap API with Partial Upstream Results
Combine Consumer, Payment, and Address APIs with correct identifier dependencies, partial success, bounded timeouts, and complete response fields.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerBuild a Running Late-Order Refund Workflow as Separate Python Services
Build a continuously running Python system of separate services that executes a small workflow graph in which late orders trigger refunds, then discuss new features, API evolution, adding payments, and testing. It tests scoping under time pressure, service boundaries, idempotent refunds, and effective AI-assisted development.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerBuild a Three-Service Refund Workflow over HTTP
Implement and orchestrate a multi-service refund pipeline over HTTP, ensuring idempotent execution, safe concurrency limits, and crash recovery across separate process boundaries.
Software Engineering FundamentalsTechnical Screendistributed-systemshttp-apisidempotency - DoorDashMediumSoftware EngineerBuild an Order-Exception Microservice with Explicit Refund Policies
Design and demonstrate a local service for missing or delayed orders, with explicit refund rules, duplicate handling, and auditable decisions.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerBuild and Debug a Dasher-to-Order Assignment Service, Then Prepare It for Production
A DoorDash onsite exercise to finish and debug starter code for a service that assigns delivery drivers to orders. It tests constant-time bookkeeping, defending a list versus hash map storage choice, invariant-based testing, and how to make the service safe and scalable in production.
Software Engineering FundamentalsOnsite - DoorDashHardSoftware EngineerCompare front-end state management approaches
DoorDash software-engineer onsite front-end question: compare Redux with modern state and data management approaches (Redux Toolkit/RTK Query, React Query, SWR, Zustand, Recoil, MobX, Context) and design an end-to-end strategy for a React SPA that needs offline viewing, pagination, optimistic updates, and error retries. It tests separating client UI state from server cache, caching/invalidation, performance, type safety, testing, and an incremental migration plan off Redux.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerDebug Round-Robin and Consistent-Hash Routing
This problem tests the ability to identify flaws in load balancing implementations by evaluating consistency, distribution, and edge-case handling in Round-Robin and Consistent Hashing logic.
Software Engineering FundamentalsOnsiteLoad-BalancingConsistent-HashingDistributed-Systems - DoorDashMediumSoftware EngineerDebug a Random Dasher Registry
Debug a random dasher registry backed by a dense array and an ID-to-index map. Repair empty and swap-delete edge cases, preserve representation invariants, narrow error handling, and extend the design for concurrency and slow dependencies.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerDebug a Round-Robin Load Balancer, Then Implement Consistent Hashing
Debug a round-robin load balancer that must keep strict rotation while servers are added and removed, then implement a consistent-hash ring that gives each key a stable server. It tests off-by-one and index-mutation bugs, thread safety, stable hashing, virtual nodes, lookup cost, and how many keys move on membership changes.
Software Engineering FundamentalsOnsite - DoorDashHardSoftware EngineerDebug a cache incident end-to-end
This question evaluates a candidate's ability to diagnose and debug production cache incidents, testing competencies in distributed caching, observability, incident response, root-cause analysis, and the operational impact on microservice latency.
Software Engineering FundamentalsTechnical Screen - DoorDashHardSoftware EngineerDebug the Last-Element Random Allocation Case
Implement and test an O(1) randomized pool that avoids and deterministically tests against the classic self-swap regression when removing the tail element.
Software Engineering FundamentalsOnsiteHash TableDesignTesting - DoorDashMediumSoftware EngineerDesign a Durable DAG Workflow for Order Refunds
This problem tests the ability to architect a robust, fault-tolerant workflow engine capable of managing complex state transitions and ensuring transactional integrity in distributed systems.
Software Engineering FundamentalsOnsiteSystem DesignDistributed SystemsWorkflow Engine - DoorDashMediumSoftware EngineerDesign a Resilient Bootstrap API Aggregator
Design a resilient bootstrap aggregation service that fetches critical initial state for a mobile app on launch. Tests interface design, concurrent I/O, partial failure handling, and operational trade-offs.
Software Engineering FundamentalsTechnical ScreenAPI DesignConcurrencyResilience - DoorDashMediumSoftware EngineerDesign an API for pay computation with retries
Assesses the candidate's ability to design robust HTTP APIs covering endpoint modeling, request/response schemas, datetime formats, idempotency strategies, retry semantics, validation/error codes, and observability for pay-computation services.
Software Engineering FundamentalsOnline Assessment - DoorDashMediumSoftware EngineerExplain a Project's Most Complex Technical Component in Depth
Explain a project's most complex technical component through its invariants, design alternatives, implementation details, and failure-case validation.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerFilter Open Restaurants Through Existing Domain APIs
Implement an orchestrator service that coordinates calls to a directory API and an operating-hours API with bounded concurrency, short-circuit filtering, resilient error handling, and in-memory caching.
Software Engineering FundamentalsTechnical Screenconcurrencycachingsystem-integration - DoorDashMediumSoftware EngineerFix a Round-Robin Load Balancer, Then Implement Consistent Hashing
A debugging-style coding round on request routing: make a round-robin load balancer behave correctly as servers join and leave, then implement consistent hashing so requests with the same key stay on the same server. It tests careful state handling, concurrency, edge cases such as an empty pool, and reasoning about how many keys move when membership changes.
Software Engineering FundamentalsOnsite - DoorDashEasySoftware EngineerHandle payment-service outages
This question evaluates a candidate's competence in designing fault-tolerant payment workflows and operational resilience, covering concepts such as idempotency, retry strategies, queuing and dead-letter handling, circuit breaking, reconciliation, and monitoring.
Software Engineering FundamentalsOnsite - DoorDashHardSoftware EngineerHow to prepare for AI-assisted coding interviews?
Tests your ability to critically evaluate, debug, and refactor AI-generated code for a real-time order batching service under concurrent access, edge-case constraints, and strict correctness requirements.
Software Engineering FundamentalsOnsiteconcurrencysystem-designrefactoring - DoorDashHardSoftware EngineerImplement Bootstrap-like responsive utility classes
This question evaluates proficiency in front-end engineering, including CSS utility system design, responsive grid layout, semantic HTML, accessibility (ARIA and focus management), form validation, asynchronous submission patterns, and lightweight JavaScript for interactivity and telemetry.
Software Engineering FundamentalsOnsite - DoorDashMediumSoftware EngineerImplement a Consistent Hash Ring
This problem tests your ability to implement a distributed hashing mechanism that minimizes data movement when adding or removing nodes.
Software Engineering FundamentalsOnsiteHashingDistributed SystemsData Structures
Disney
DocuSign
DoorDash