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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.
- 9403
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- 546
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- 11
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Showing 751–780 of 2336 results
- DoorDashMediumSoftware EngineerCalculate Driver Payments
Implement a payout calculation system for delivery drivers by deduplicating order logs, merging overlapping active-time intervals, and computing base pay, delivery bonuses, and tips.
Coding & AlgorithmsOnsiteintervalssortinghash-table - 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 EngineerCompute cart total with best promotion
This question evaluates numerical reasoning for monetary calculations, handling of multiple promotion types, precision and rounding considerations, and edge-case handling such as empty carts and clamping totals within the Coding & Algorithms domain.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerCompute dasher pay from deliveries
This question evaluates competency in data manipulation, schema design and validation, time-based aggregation, pay-computation logic, and handling of edge cases using SQL or Python.
Data Manipulation (SQL/Python)Onsite - DoorDashMediumSoftware EngineerCompute dasher pay with peak-hour query
This question tests the ability to handle overlapping time intervals and perform weighted calculations based on time-based pay multipliers.
Coding & AlgorithmsOnsiteAlgorithmsIntervalsData Processing - DoorDashMediumSoftware EngineerCompute dasher payout from API data
This question evaluates a candidate's proficiency in data manipulation and transaction aggregation using SQL or Python, encompassing time-zone-aware timestamp handling, pagination, late or missing events, cancellations and negative adjustments, rounding rules, and itemized breakdowns.
Data Manipulation (SQL/Python)Onsite - DoorDashMediumSoftware EngineerCompute nearest-exit distances in a grid
Compute nearest-exit distances in a grid 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 - 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 - DoorDashMediumSoftware EngineerDebug a driver assignment bug
This question evaluates debugging, root-cause analysis, unit/integration test design, observability, and system-resilience competencies within the Coding & Algorithms domain, emphasizing practical skills in reproducing failures, isolating defects, and implementing targeted fixes.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerDebug and refactor a legacy module
This question evaluates debugging, refactoring, naming and exception handling, input validation, code structure, and concurrency-safety design skills within a legacy codebase, requiring both hands-on code changes and higher-level reasoning about immutability, confinement, synchronization, and concurrent data structures.
Coding & AlgorithmsOnsite - 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 EngineerDebug using logs and allocate tasks
This question evaluates a candidate's skill in log-driven debugging, production incident investigation, and cross-functional task allocation, covering competencies such as structured and contextual logging, correlation identifiers, noise reduction, minimal reproducibility, feature-flagged isolation, triage coordination, hypothesis tracking, root-cause confirmation, regression prevention, and blameless postmortems. It is commonly asked to assess operational troubleshooting and teamwork under production uncertainty within the Coding & Algorithms category, testing practical application of debugging techniques alongside conceptual understanding of incident management and process-level coordination.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerDescribe your most impactful recent project
A DoorDash software-engineering onsite behavioral question asking you to walk through your most impactful recent project: the problem, your specific role, measurable impact, a key technical decision and its trade-offs, how you handled scaling and reliability, a risk or failure you hit, and what you'd do differently. Includes a structured STAR-plus-deep-dive framework and a worked real-time-dispatch example.
Behavioral & LeadershipOnsite - DoorDashMediumSoftware EngineerDesign Food Ratings and Driver Payouts
This question evaluates system design competencies such as API design, data modeling and storage selection for aggregated 5-point ratings, handling user-generated posts and likes, service decomposition, consistency trade-offs, scalability, and designing a monthly batch payout pipeline for driver earnings.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign Food-Item Reviews, Ratings, and Mutable Vote Counts
Design item reviews and votes with purchase eligibility, unique reviews, rating aggregates, reliable counters, pagination, and recoverable caching.
System DesignOnsite - DoorDashHardSoftware EngineerDesign a 3-day donation platform
This question evaluates competency in designing scalable, highly available payment-enabled distributed systems, including skills in traffic spike handling, idempotency and reconciliation, real-time totals and leaderboards, latency and throughput planning, and compliance/privacy considerations.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign a Donation Service with Reliable Payment and Payout Tracking
Design donation collection and charity payouts with a PSP, idempotent state transitions, durable ledger records, asynchronous provider events, and reconciliation.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign a Donation System for a Three-Day Fundraising Campaign
Design a donation system for a fundraising campaign that runs for exactly three days, where donors choose a charity, pay through a payment processor and see running totals. It tests payment idempotency and reconciliation, handling a time-boxed traffic burst, avoiding write hotspots on totals, and fraud protection.
System DesignOnsite - 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 Food Item Review and Customer Reward System for a Delivery App
A DoorDash system design prompt to build a food item review system for a delivery app that also rewards customers for reviewing. It tests product judgment on open questions, verified-purchase writes, cached rating aggregates, and designing a practical, abuse-resistant reward program with reliable crediting.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign a Food Rating System
This problem tests your ability to design a distributed, read-heavy rating and review system that handles high concurrency and ensures data integrity.
System DesignOnsiteDistributed SystemsCachingAPI Design - DoorDashMediumSoftware EngineerDesign a Food Review Platform
Design a food review platform for discovery, ratings, review text, optional dish-level content, and trusted aggregates. Define entity and review contracts, search and read paths, moderation, abuse resistance, privacy, scaling, and operational recovery.
System DesignOnsite - DoorDashHardSoftware EngineerDesign a Food Review System for a Delivery App, Focused on the Database Schema
System design question for the review feature of a food-delivery platform, where customers rate and review the food from delivered orders and others browse ratings. The focus is database schema design: tables, keys, constraints, indexes, rating aggregates, and how edits, deletes and moderation keep them correct.
System DesignOnsite - DoorDashMediumSoftware EngineerDesign a Food Review and Voting System
Design a scalable review and voting platform for dishes and restaurants, focusing on transactional vote changes, aggregate counter consistency, hot-item read/write scaling, and stable pagination.
System DesignOnsiteDistributed SystemsDatabasesCaching - DoorDashHardSoftware EngineerDesign a Food-Item Review System
Design an item-level review and rating platform for food delivery that handles high-throughput reads, asynchronous sentiment and moderation pipelines, and near real-time score aggregations.
System DesignOnsiteDistributed SystemsData ModelingCaching - DoorDashMediumSoftware EngineerDesign a Menu Item Review and Rating System for a Food-Delivery Platform
A system design question on a menu review feature for a food-delivery platform, where customers rate and review the menu items they ordered. It tests requirement prioritization, detailed review schema and API design, rating aggregation, caching and moderation, and time management that still reaches a deep dive.
System DesignOnsite - DoorDashHardSoftware EngineerDesign a Multi-Service Workflow Engine
Design a resilient, distributed workflow orchestration engine capable of executing multi-step business processes across heterogeneous services with strict guarantees around durability, idempotency, and failure recovery.
System DesignOnsiteDistributed SystemsSaga PatternWorkflow Engine - DoorDashEasySoftware EngineerDesign a Real-Time Monitoring System
This problem tests your ability to design a high-throughput observability pipeline capable of ingesting, storing, and alerting on time-series metrics from a distributed fleet of services.
System DesignOnsiteObservabilityTime-SeriesDistributed Systems
DoorDash