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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 781–810 of 2336 results
- DoorDashMediumSoftware EngineerDesign a Refund Workflow as a Directed Acyclic Graph
Design a resilient, stateful workflow orchestration engine to process complex order refunds as a Directed Acyclic Graph (DAG), ensuring idempotency, crash recovery, and financial consistency.
System DesignOnsitesystem-designdistributed-systemsworkflow-engine - DoorDashMediumSoftware EngineerDesign a Review and Rating System for Food Delivery Menu Items
Design a review and rating system for a food-delivery platform, where customers review the individual menu items they received and every menu shows each item's rating. It tests data modeling, purchase verification, incremental rating aggregation, caching for read-heavy menus, moderation, and handling bursts on popular items.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign a Sliding-Hour Top-Restaurants Service
This problem tests the ability to design a high-throughput, real-time analytics system that maintains a top-k leaderboard over a sliding time window.
System DesignOnsiteStreamingAnalyticsDistributed Systems - DoorDashMediumSoftware EngineerDesign a Store Recommendation System and Explain ML Trade-offs
Design a personalized store recommendation feed for an on-demand delivery platform and evaluate key machine learning modeling trade-offs.
ML System DesignOnsiteRecommendation SystemsMulti-Task LearningRanking - DoorDashHardSoftware EngineerDesign a distributed cron job scheduler
Design a distributed cron job scheduler evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign a donations service with 3-day rolling totals
This question evaluates a candidate's competency in designing scalable, low-latency streaming data systems, covering event-time windowing, rolling-window aggregation, idempotency for duplicate events, late/out-of-order handling, and auditability.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign a hierarchical path registry
Design a hierarchical path registry evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - DoorDashHardSoftware EngineerDesign an Online Course Marketplace Review System Schema
Design the review and rating feature of an online course marketplace where only learners who completed a course may rate it, with the discussion centered on table design, keys, constraints, and the indexes each read path needs.
System DesignOnsitesystem-designdatabase-designschema - DoorDashHardSoftware EngineerDesign an async donation payment platform
This question evaluates a candidate's ability to design scalable, reliable payment systems and asynchronous processing pipelines, covering competencies in distributed systems, idempotency, data modeling, security/PCI compliance, retry and dead-letter strategies, and observability.
System DesignOnsite - DoorDashHardSoftware EngineerDesign consistent hashing for sharding
This question evaluates understanding of consistent hashing, replica placement, dynamic membership, weighted load distribution, rebalancing impact, and related distributed-systems competencies for routing and sharding.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign dasher-to-order assignment algorithm
This question evaluates a candidate's skills in real-time algorithm design and systems thinking for dynamic matching and optimization, including scalability, time/space complexity analysis, and handling partial or delayed information.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerDesign dynamic connectivity with alive nodes
This question evaluates understanding of dynamic graph data structures, connectivity algorithms, state management for node activation/deactivation, complexity analysis, and concurrent operation considerations.
Coding & AlgorithmsOnsite - DoorDashHardSoftware EngineerDesign review system with voting and rewards
This system design question evaluates a candidate's ability to architect a scalable review platform with voting, counter aggregation, and rewards at high traffic volumes. It tests practical knowledge of distributed counter strategies, idempotent write handling, read/write path separation, and abuse prevention — core competencies assessed in senior software engineer interviews.
System DesignOnsite - DoorDashMediumSoftware EngineerDiscuss project experience and teamwork
Discuss project experience and teamwork evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipOnsite - DoorDashMediumSoftware EngineerExplain AI Tool Use, Model Selection, and Engineering Validation
Explain practical AI use across coding and summaries, with honest contribution measures, task-specific model choices, validation, and cost awareness.
Behavioral & LeadershipOnsite - DoorDashMediumSoftware EngineerExplain Performance, OKRs, Failure, and Project Learning
This question tests your ability to navigate complex project lifecycles by evaluating your ownership of OKRs, your response to significant failure, and your capacity for introspective learning.
Behavioral & LeadershipOnsiteLeadershipOKRsBehavioral - DoorDashMediumSoftware EngineerExplain Project Impact from Prototype to Shared Ownership
Describe a proud project's impact, evidence of time saved, transition from prototype to supported use, and cross-functional ownership.
Behavioral & LeadershipOnsite - DoorDashHardSoftware EngineerExplain Why You Are Changing Roles
This question tests your ability to articulate a clear career trajectory, demonstrating that your move is driven by professional growth rather than dissatisfaction with your current situation.
Behavioral & LeadershipOnsiteCareer StrategyCommunicationProfessionalism - 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 - DoorDashHardSoftware EngineerExplain an AI-Assisted Project
Tests your ability to articulate the engineering realities of an AI- or LLM-driven project, focusing on rigorous evaluation, production guardrails, failure modes, and personal ownership rather than high-level buzzwords.
Behavioral & LeadershipOnsiteBehavioralAI & MLSystem Reliability - DoorDashHardSoftware EngineerExplain conflict resolution and growth
This question evaluates collaboration, ownership, technical leadership, conflict resolution, incident management, decision-making, and the ability to learn from and prevent mistakes.
Behavioral & LeadershipOnsite - DoorDashMediumSoftware EngineerExplain handling conflicts and learning from mistakes
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Explain handling conflicts and learning from mistakes states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipOnsite - DoorDashMediumSoftware EngineerFind Each Cell's Nearest Source
This question evaluates understanding of shortest-path computation and distance labeling in grid-based graphs, measuring competency in algorithmic problem solving and efficient traversal strategies.
Coding & AlgorithmsOnsite - DoorDashHardSoftware EngineerFind longest common ordered restaurant list
This question evaluates a candidate's understanding of sequence algorithms, dynamic programming, and string/list manipulation by requiring computation of the longest common subsequence between two ordered lists of restaurant IDs.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerFind the Minimum Delivery Processing Speed
This problem tests binary search on the answer space to find the minimum throughput capacity required to process a set of delivery orders within a fixed deadline.
Coding & AlgorithmsOnsiteBinary SearchOptimizationMath - DoorDashMediumSoftware EngineerFind the Minimum Parenthesis Deletions and Their Positions
This problem tests string manipulation, stack-based parsing, and greedy logic to identify the indices of parentheses that must be removed to transform a string into a valid sequence.
Coding & AlgorithmsOnsiteStringsStackGreedy - 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 - DoorDashMediumSoftware EngineerGenerate the next lexicographic array arrangement
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Generate the next lexicographic array arrangement states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - 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 - DoorDashEasySoftware EngineerHow do you discuss mistakes and trade-offs?
This question evaluates competency in accountability, leadership, incident management, and product/operational decision-making within the Behavioral & Leadership domain for software engineers.
Behavioral & LeadershipOnsite
DoorDash