Doordash Software Engineer Interview Questions
DoorDash Software Engineer interview questions typically target problems grounded in logistics, real‑time event processing, and metrics-heavy product work. Expect a standard funnel: a recruiter screen, a timed technical coding screen (often on HackerRank/CoderPad), and a virtual onsite loop with two to three coding rounds, a system‑design session, and a behavioral/hiring‑manager interview. Interviewers evaluate correctness, algorithmic efficiency, scalability and reliability tradeoffs, product intuition for delivery and marketplace problems, and evidence of ownership and collaboration under ambiguity. For effective interview preparation, focus on clean data‑structures & algorithms solutions, latency and throughput considerations, and system design patterns for dispatching, caching, and monitoring. Practice with timed coding platforms and mock interviews, prepare STAR stories that demonstrate impact and conflict resolution, and be ready to explain tradeoffs and performance optimizations clearly. Polished communication, thoughtful questioning, and concrete project examples often separate strong candidates from good ones when facing DoorDash Software Engineer interview questions.
Compute courier pay and implement load balancing
Problem 1: Compute courier (delivery driver) pay You are given a sequence of delivery-related events for a courier during a day. Your task is to compu...
Design a donations service with 3-day rolling totals
Design a service that ingests donations and serves rolling 3-day donation totals. Requirements Core features 1. Ingest donation events: - Each dona...
Compute cart total with best promotion
Assume you are implementing a checkout price calculator for an online shopping cart. You are given: - A list of items in the cart. Each item has: - ...
Design API that aggregates three downstream APIs
You are given three existing HTTP JSON APIs owned by other backend services: - Service A: GET /service-a?user_id={id} → returns basic user profile dat...
Design a resilient dasher payment system
System Design: End-to-End Payouts from Order Lifecycle Events You are designing a system that computes delivery driver (Dasher) payouts from an event ...
Implement round-robin load balancer
Implement a load balancer that distributes incoming requests across N backend servers in strict round-robin order. Requirements: ( 1) Support addServe...
Design a 3-day donation platform
Design: Online Donation Platform for 3‑Day Campaigns Context You are designing an online donation platform optimized for short, 3‑day fundraising camp...
Debug a driver assignment bug
Given a service that selects the best delivery driver ("dasher") for an order, users report incorrect assignments. With a provided codebase and failin...
Design cron scheduler and reward/review system
System Design: Company-Wide Scheduler Platform and Employee Review & Rewards System You are designing two platforms for a fast-growing, multi-tenant t...
Find the nearest city sharing axis
You are given N cities, each with a unique name and integer coordinates (x, y). For any query city, return the nearest city that shares either the sam...
Implement and compare round-robin and consistent hashing
Implement a round-robin load balancer that selects among service nodes, skipping unavailable nodes and wrapping around correctly. Fix typical pitfalls...
Implement image carousel with comments and upvotes
Implement an image carousel that supports: 1) cycling forward/backward and autoplay with a configurable interval; 2) a per-image comment thread with c...
Deep-dive a project architecture
Deep Technical Review of a Recent System Context: You are interviewing for a system design/engineering role. Select one substantial project you worked...
Design an async donation payment platform
System Design: Online Donation Platform for a 3-Day Campaign Context You are designing a donation platform for a time-bounded, high-traffic, three-day...
Design consistent hashing for sharding
Design a Consistent-Hashing Router with Replication You are building a stateless router that maps arbitrary keys (for example, request IDs or cache ke...
Find longest common ordered restaurant list
You have two delivery drivers who each have a pickup plan represented as a list of restaurant IDs (strings). Because there is only one car, the combin...
Describe project impact and feedback
Behavioral Prompt: Describe a Recent Project You Led Context You are interviewing for a Software Engineer role in an onsite Behavioral & Leadership ro...
Find nearest courier for each customer
Given two sets of 2D points: customers C = {c1..cn} and active couriers D = {d1..dm}, return for every customer the nearest courier by geographic dist...
Design consistent hashing with a sorted map
Consistent Hashing with a Sorted Map (Virtual Nodes) Context You are building a client-side library to map arbitrary keys to backend nodes (cache/stor...
Debug round-robin, DashMap, and simple cache
You are given a service that routes requests to a list of nodes, each marked as either available or unavailable. The pickNode() function is intended t...