DoorDash

Large Enterprises

DoorDash is a leading online food ordering and delivery platform that connects customers with local restaurants and merchants. It is known for its logistics network of delivery drivers (Dashers) and has expanded into grocery, retail, and convenience delivery.

414total notesUpdated 1 month ago

Every question, shortened answers

Browse all 414 notes for DoorDash. Each answer is trimmed to its first line — create a free account to read them in full.

DoorDash·Software Engineer·Technical Phone Screen

Jul 2026

DoorDash software engineer round, one algorithmic problem the whole time. Pretty standard multi-source BFS setup but the edge case around empty grids tripped me up a bit.

Given a grid of 0s and 1s where 1s are source cells, return a same-sized matrix where each cell contains its shortest distance (4-directional) to the nearest source cell. Source cells have distance 0. If no source cells exist, every cell should return -1.

“I knew it was BFS pretty fast, the multi-source part clicked quickly too.”

1Sign in to interact

View Post

DoorDash·Data Scientist·Technical Phone Screen

Jul 2026

DoorDash data scientist interview with a product analytics case built around a geo-targeted feature launch. The core of it was interpreting a retention chart under data constraints, which sounds manageable until you're actually in it.

You're evaluating whether to launch a new geo-targeted feature with limited traffic data. Walk through how you'd build the business case: what data you'd need, which metrics matter, and how you'd define success.Looking at a retention curve comparing test vs. control groups, what hypotheses can you pull from it and what would you do next?

“I started with the metrics layer and worked backward, which felt right in the moment but I think I skipped over some data availability assumptions too quickly.”

2Sign in to interact

View Post

DoorDash·Software Engineer·Onsite - System Design / Architecture

Jul 2026

System design round at DoorDash for a software engineer role. The whole thing was basically one big consistent hashing problem and they wanted a lot of depth on it, not just the concept but actual implementation decisions.

Design and implement a consistent hashing system that distributes keys across a dynamic set of backend nodes, including API design, virtual nodes, hash function selection, and handling node additions and removals with minimal key movement.

“This was a meaty one.”

1Sign in to interact

View Post

DoorDash·Software Engineer·Technical Phone Screen

Jul 2026

DoorDash coding screen for a software engineering role. One problem, delivery event processing, and it was more involved than it looked at first glance.

You're given a list of delivery event records for a single dasher, each with an order ID, an event type (one of CREATED, ACCEPTED, PICKED_UP, DELIVERED, or CANCELED), and a timestamp string that may include timezone info and may not be sorted. Compute the dasher's total pay given a rate per minute, where an order is active from ACCEPTED until DELIVERED or CANCELED, rounding down to whole minutes. Handle malformed sequences explicitly.

“The problem sounds like a simple loop until you realize the timestamps aren't sorted and might have timezone offsets.”

1Sign in to interact

View Post

DoorDash·Software Engineer·Onsite - System Design / Architecture

Prefer not to say

Jul 2026

DoorDash system design round, one big question about state management that sprawled into basically every frontend architecture topic imaginable. Felt like they wanted to see if I could hold a coherent opinion across ten different sub-problems at once rather than just recite library docs.

Compare Redux with modern frontend state and data management approaches, and design an end-to-end strategy for a React SPA that needs to consume multiple APIs, support offline viewing, pagination, optimistic updates, and error retries.

“This question is massive and they absolutely know it.”

1Sign in to interact

View Post

DoorDash·Software Engineer·Technical Phone Screen

Jul 2026

DoorDash software engineering interview with a meaty system design coding question. The problem was a custom hierarchical key-value store built on UNIX-style paths, which sounds manageable until you realize how many edge cases they actually want you to cover.

Design and implement a hierarchical key-value store that operates on UNIX-style absolute paths, supporting create, set, get, and remove operations. Each operation has specific failure conditions: create fails if the parent doesn't exist or the path already exists, set fails on missing paths, and remove fails if the node has children. You need to choose your return types, define path syntax assumptions, justify your data structure choices, analyze complexity, and write unit tests covering edge cases.

“This was a lot to hold in your head at once.”

1Sign in to interact

View Post

DoorDash·Software Engineer·Technical Phone Screen

Prefer not to say

Jul 2026

DoorDash coding round for a software engineer role. Three-part exercise: implement a small service class from a spec, extend it with a new requirement, then write unit tests covering the full thing. Felt more like a take-home in spirit even though it was live.

Given a written spec for a small service class with no external dependencies, implement the core logic using if/else control flow and proper input validation. State your assumptions explicitly.Extend the class you just implemented to handle an additional requirement based on assumptions you clarify with the interviewer.Write unit tests for both parts of the implementation, covering happy paths, edge cases, and error handling.

“The spec was short but I still managed to overthink the input validation part.”

3Sign in to interact

View Post

DoorDash·Data Scientist·Technical Phone Screen

Jul 2026

DoorDash data science interview with a meaty marketplace diagnosis case that turned into a full experiment design problem. The scope was broader than I expected and the second half caught me pretty flat-footed.

Completed orders in the Los Angeles market dropped meaningfully. Walk through how you'd investigate this end to end.The investigation points to merchants being online fewer minutes per day. Design an experiment to test an incentive program meant to fix that.

“I started with the funnel breakdown which felt right, app sessions down to completed orders, but I kept second-guessing whether to lead with supply or demand.”

2Sign in to interact

View Post

DoorDash·Software Engineer·Onsite - System Design / Architecture

Prefer not to say

Jul 2026

System design round at DoorDash focused entirely on a donation platform problem. It was one of the more sprawling prompts I've seen, covering everything from payment idempotency to GDPR compliance to counter consistency, all in one session.

Design an online donation platform built around short 3-day campaigns. Walk through functional requirements, non-functional goals, and traffic estimates before getting into the architecture.What APIs and data models would you define for this system? Think about entities like Campaign, Donation, Donor, PaymentIntent, and Receipt.How would you handle payment processing, including idempotency, retry logic, and reconciliation with the payment provider?+5 more

“I spent too long on the requirements phase and the interviewer had to nudge me to move on.”

8Sign in to interact

View Post

DoorDash·Software Engineer·Onsite - System Design / Architecture

Jul 2026

DoorDash system design round focused entirely on building a real-time driver assignment system from scratch. Pretty intense scope for a single session, covering everything from objectives and constraints to algorithms and failure modes.

Design a real-time system that assigns delivery drivers to incoming orders. Walk through your objectives, constraints, data structures, algorithm choices, and how you'd handle scale and partial information.

“This one sprawled fast.”

1Sign in to interact

View Post