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DoorDash Product Manager Interview Guide

Detailed, specific guidance on the DoorDash Product Manager interview process - with a breakdown of different stages and interview questions asked at each stage

The role of a DoorDash Product Manager

A PM at DoorDash is responsible for owning end to end product strategy, delivery, and impact for a component or product within the DoorDash ecosystem. You'd own a key aspect of the ecosystem which directly ties back into a key metric for the company; and it could be across any part of the 3-way marketplace (dashers/riders, restaurants and bookers).

From a day-to-day point of view - Product at DoorDash will involve staying on top of the market landscape (i.e. keeping track of both macro trends and competition); identifying customer needs; building out a product vision & strategy - and then executing on it, all the way from working with UX for designing a great customer experience, with Engineering for high performance and reliability, to Data for extracting insight from experimentation and identifying iterations.

DoorDash interviews can get pretty challenging -the company pays well - but also aggressively filters out candidates who miss a trick. Broadly speaking, you'd have to index well on being able to strategize and think big while solving real customer problems (tested via Product Sense interviews), execute reliably and pragmatically (tested via Product Prioritization and Product Analytics), and being a good "working fit" for DoorDash' culture (tested via "Values" interviews).

This guide is going to deepdive through the process and provide recent interview questions for you to mull over when you're preparing for the interview. When you're ready you can also book mock interviews with DoorDash PM coaches to "sense check" your readiness level.

The interview process is divided into several stages:

• Phone screen with a recruiter
• Take home assessments - occurring at decreasing frequency; roughly 25% of all candidates reporting a take-home in the last 12 months.
• Phone screen with hiring manager and/or current PM
• (Virtual) On-site interviews - 3-4 rounds covering Product Sense, Product Analytics, Product Prioritization and Values

The process typically takes 4-6 weeks.

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Applying to DoorDash for a PM role

Apply online on the DoorDash website; or if you can pull it off - get a referral. You might also be approached by a recruiter. Regardless of the channel - make sure to customize your resume a bit to make it relevant for the role you've applied. This might not have been needed in 2021 and 2022 with the hot job market - in these times, you absolutely need to stand out given the super high number of candidates applying for a role.

Relevant Guides

Doordash pm round 1: recruiter screen.

The first interview will be conducted over the phone with a product management recruiter. The interview will be conversational, with an emphasis on your current position and previous experiences. This interview is an excellent chance to discuss any questions you might have about the role or interview process. Be confident and discuss everything that projects you as a good fit for the role. The interview will last up to 30 mins.

What the interviewer will assess

• Your past experiences & their relevance to the role
• Your interest & motivation in applying to DoorDash
• Your ability to fit in with DoorDash' culture
• Be prepared with a short brief intro to get the "Tell me about yourself" question out of the way.
• Be super "on top" of every line item on your resume. The recruiter can cherry pick stuff relevant to the role and they'd want to dig into this.
• Use the opportunity to find out more about the role, what the hiring manager is looking for, how the org is structured, what the recruiter thinks will be key challenges etc. This is a great opportunity to customize your answers further down.
• *Don't share salary expectations upfront - you won't be doing yourself a favour. We'll be writing a separate article on how to field this question in a couple of weeks and will link this in here at that point.

Interview Questions

• What do you know about DoorDash?
• Why are you looking for a new role?
• Are you familiar with DoorDash' business model?
• Why do you feel the DoorDash Product Manager role is a good fit for you?
• Tell me about yourself
• What do you think is your most relevant past experience for this role?
• Are you interviewing anywhere else in parallel?
• What are your salary expectations?

Watch these videos

Doordash pm interview: take-home assessments.

This is an Analytical exercise. You're given a set of hypothetical data usually in excel worksheets and either have to extract insights from them; or answer specific questions.

Not all candidates have to do this step; some skip it entirely. Depends on a combination of what the hiring manager and recruiter decide; whether you're going in via referral; and how good your perceived fit for the role is. Based on candidate reporting (could be inaccurate, but is a decent proxy) - only 25% of all candidates reported receiving this in the last 12 months.

For those who do receive this assignment - they reported it took roughly 3h to complete.

Read these articles

Doordash pm round 2: phone screen.

The second interview is another phone screen, except this time it is arranged by a Hiring Manager who may be accompanied by a currently working PM. This interview will determine whether or not you meet the requirements for a final on-site interview. Note that:

• The interview will be about 40 mins long.
• The PM interview at DoorDash is divided into two parts: product prioritization and product sense.
• Can you handle a broad problem statement (often unrelated to DoorDash) all the way from understanding the problem, clarifying relevant constraints, thinking of market landscape and user challenges, to a proposed set of solutions - all within a super short 20-25min?
• Can you make pragmatic but relevant tradeoffs when it comes to narrowing down your answer at different stages. Eg the customer segment to focus on; a particular problem or pain point to dig into; or a solution to start exploring in more depth.
• Can you isolate key metrics which give are a good proxy for directionality and impact?
• Can you communicate your thought process succinctly yet effectively?
• If you're interviewing for a senior role - can you drive the conversation alongside your interviewer rather than purely reacting - in a logical way that flows rather than rigidly adheres to a theoretical framework.
• If you're interviewing for a Principal or Group role - can you call out the opportunities to leverage your space/org; the complexity you'll encounter therein; and the ways in which you would approach these.
• Ultimately - nearly all your core PM competencies (product strategy, ideation, brainstorming, prioritization, MVP thinking, execution, metrics and iteration skills), are tested albeit slightly superficially in this round.
• There's a tremendous amount of area being covered in this interview. You want to be super concise - you don't want your interviewer noting "didn't have a chance to explore xyz" in their interview feedback.
• Make sure to leverage opportunities to flag fit. Eg. "I've actually built a product for a similar customer segment at xyz; and my insight was that they often struggle with abc" both shows an appreciation for customer problem while driving home your unique fit for a role.
• Practice. Extensively. Can't stress this enough. We're a mock interviews platform so we have a biased take on this - but honestly; this isn't something you want to go unprepared into since interviews have a habit of going down tangents you can't anticipate beforehand; and it's less the "content" part of the practice and more the "mindset" that practicing with coaches can hep you get into, that is the most valuable part of working with a coach. For DoorDash specifically, Prepfully has 2 excellent Product Managers from DoorDash here who provide 1-1 interview coaching.
• If you were a Product Manager at DoorDash, which space would you aim to explore expanding into for the company?
• Suppose you are a PM at DoorDash. What steps will you take to improve engagement?
• You own six pizza shops in town and want to increase your sales. Would you create a smartphone app or use Uber Eats?
• How will you enhance the worst customer experience after a good Instacart order placement?
• DoorDash wants to expand to a new market - what would you think about before taking action?
• How can you boost DoorDash's post-booking experience after the user has placed their order?

DoorDash PM Round 3 - Virtual Onsite interviews

The final stage of the DoorDash Product Manager interview process is a series of conversations - previously onsite; but post-covid virtually. These will be with a range of PMs and Senior PMs - depending on the seniority you're interviewing for there will also be Directors or Group PMs involved.

There are 4 broad interviews, and an extra one for People manager roles

• Product Sense
• Product Analytics
• Product Prioritization
• People Management & Leadership - only for Group Product Manager roles.

Some roles will also involve

• Take home assignment presentation
• Technical interview
• Product Sense: Can you handle a broad problem statement (often unrelated to DoorDash) all the way from understanding the problem, clarifying relevant constraints, thinking of market landscape and user challenges, to a proposed set of solutions? Can you think strategically, but also pragmatically; and in a way that allows you to demonstrate your skills across a wide range of topics in roughly 45min?
• Product Prioritization: Can you make relevant tradeoffs? Remember - it isn't prioritization if it's obvious and doesn't hurt. Your interviewers are seeing if you are aware of how difficult some decisions can be; and your approach to navigating problems you might create when you accept these tradeoffs. Ultimately you want to be able to smartly narrow down your answer at different stages (I gave a few examples above) - but also should be able to think of how you would approach prioritization in theoretical scenarios your interviewer might present.
• Product Analytics: The goal here is to see if you can leverage data to drive insights and actions. Three types of questions that typically come up here. 1) What metrics would you use to track success; why; what tradeoffs are involved in choosing them etc. 2) How would you react to a metric going a certain way in - either in an experiment (eg. you rolled out a new change and clicks went up but bookings went down - what do you do next), or to a metric going negative without a directly associated event (eg. you come in and see Dasher delivery timings are up by 25%; what could be happening) - so troubleshooting equivalent questions. 3) How would you come up with a hypothesis to drive some specific sort of impact, what proxy metrics would you track to (in)validate it - what secondary metrics could provide more insight etc. Finally there's a 4th which is nearly never asked now - opportunity sizing. How many Dashers do you need to cover New York? sort of question. Your interviewers are trying to get an idea of how comfortable you are with numbers and using them within your decision making framework.
• Values: This one is the most straightforward. Motivational and behavioral fit with DoorDash. Will you succeed in Doordash' ecosystem, way of working, involving stakeholders in the right way etc.
• People Management and Leadership: Mostly only needed for Group PM and Director roles; but topics span from building/growing your team; managing performance - both high performers and low performers; helping your directs grow their career and craft; challenges and opportunities you've identified and leveraged etc.
• Product Sense: Practice thinking day to day about products you use (both tech and non-tech). And once you feel you're ready - practice with peers or coaches to make sure you're approaching these questions the right way.
• Product Prioritization: Think in advance of difficult tradeoffs you've had to make. Obvious ones are tech debt vs features. Harder ones could be small step iterations & wins vs long term bets. The truly insightful ones that reveal your approach to the craft will be more meta-level such as "catching up to a competitor" vs "building a differentiator". Try to then apply this previous experience and knowledge in the context of an interview. Frame it in a way that shows that you've had to deal with this sort of thing before.
• Values: 1) Ready up on DoorDash' values; make sure to embed themes within your answers *in the context of a Product Manager at DoorDash* since this is effectively a shortcut to the checkboxes your interviewer will inevitably need to tick in their interview rubrik. 2) Prepare your stories beforehand optimizing for the key takeaway you want your interviewers to have. Too many candidates treat this interview like a fireside chat. That's a mistake - your interviewer is trying to understand if you can handle really difficult, tricky situations. Getting to know you and your past situations is the "pleasant side effect" - the real question they are trying to answer is going to be something like "Hey, I know this team's PM is going to have a hard time with the UX person given the really difficult tradeoffs that need to be made between user experience and revenue. Let me maybe ask a question that helps me suss out how they'll react", and the question is innocently going to be framed as "Tell me about a time you couldn't reach an agreement with a peer". You want to make sure you deliver your takeaways, learning and competence extremely clearly rather than leaving it for the interviewer to "extract" from your answer.
• People Management: Don't prepare only for the happy path - most interviewers will ask you about the challenges since this is where the biggest existential issues to a team's success can occur. Make sure to have some honest examples of difficult conversations you've had to have, as well as of times where you didn't manage to make things work out. Everyone fails sometimes - they want to see you having learnt from the failure in a direct and tangible way; and you need to have these examples ready.
• What would you prioritize next if you were in charge of LinkedIn?
• How would you develop the AirBnB recommendation algorithm for guests?
• How do you define success when it comes to Yelp reviews?
• You work as a PM for a food delivery app. Over the last week, restaurant supply has decreased by 10%. What are you going to do about it?
• At Instacart, you work as a PM. What do you believe can go wrong after the customer places an order?
• What are the most common issues that arise during the delivery process after a customer has placed an order?
• As a PM at DoorDash, what improvements would you want to make first?
• Create a product that assists teenagers in finding new places to eat.
• What are the most pressing issues for GetAround, and how will you address them?
• Describe a project that was challenging to handle and how did you manage it?
• What is your communication and leadership style?
• When do you realize a project has gotten off track?
• How can you get a project back on track if it is falling behind schedule?
• Do you have budgeting experience?
• Have you worked with remote teams or outsourced resources?
• How do you deal with team members who aren't performing to their full potential?
• How do you cope with being overburdened or underperforming?
• What's your approach to collaborating with your stakeholders?
• What is the most serious misstep you've taken on a project?

Practice with a DoorDash PM. Get specific, granular, targeted advice on your performance.

Responsibilities of a product manager at doordash.

The responsibilities of a PM at DoorDash across roles can broadly be seen as-

• End to end ownership of key product areas, from strategy to execution. For instance, conduct market research, analyze customer insights, and identify opportunities for product improvements and innovations.
• Own the product strategy and vision, define the product roadmap and alignment, and help drive your team through the execution. You will be monitoring KPIs  and metrics to assess the effectiveness of product initiatives and drive data-informed decision-making.
• Create direct relationships with merchants, consumers and Dashers to deeply understand their perspectives and pain points as you develop your strategy. It’s crucial to be able to incorporate customer insight into your product planning.
• Grow and scale a business line within DoorDash. Identify growth opportunities and develop strategies to expand and scale a specific business line within the DoorDash platform.

Skills and Qualifications needed for Product Managers at DoorDash

Here are some of the skills and qualifications that we’ve seen DoorDash Hiring Managers typically filter for, in PM candidates.

• For most roles, you’ll be expected to have at least 5+ years of industry experience in PM roles.
• Having prior experience in user-facing roles within industries like eCommerce, technology, or multi-sided marketplaces can be really helpful since you have a lot of context relevant to DoorDash on your hands.
• Showcase your ability to drive product strategy, align product vision with business objectives, and execute on product roadmaps. 
• Demonstrate your experience in presenting business reviews and insights to senior executives. Effective communication with stakeholders at all levels is crucial in Product Management, as it helps build alignment, gain buy-in, and drive decision-making.
• Prior user-facing experience in industries such as eCommerce, technology or multi-sided marketplaces will be essential.
• Emphasize your ability to thrive in a cross-functional environment. PMs work closely with operations, engineering, design, and other teams to bring products to market.

Salary Ranges

The salary range for a product manager at DoorDash can vary depending on several factors such as experience, location, and level of responsibility. It's important to note that salary ranges can also change over time due to market conditions and other factors. The salary range for a product manager at DoorDash is generally between $100,000 to $180,000 per year.

That's basically it. tl;dr the DoorDash PM interview process will consist of

1. A phone screen with a recruiter

2. (Sometimes) a take home assessments

3. Phone screen with hiring manager and/or current PM

3. (Virtual) On-site interviews - 3-4 rounds covering Product Sense, Product Analytics, Product Prioritization and Values

As I mentioned above - once you're ready with your prep and either want good quality practice with a DoorDash PM - or just a sense check of your "readiness level" on one of the interview types - book a 1-1 coaching session with a DoorDash Product Manager here .

Frequently Asked Questions

What qualifications and skills are typically required for a Product Manager role at DoorDash?

What topics are commonly covered in DoorDash's Product Manager interviews?

Is there a technical component in the Product Manager interview process at DoorDash?

How can I prepare for the product sense interviews in the Product Manager interview process at DoorDash?

Are there behavioral or situational interview questions in the process?

Relevant interview guides

Doordash Data Scientist Interview Guide

Back to Doordash

Introduction

DoorDash is making its mark as the world’s most reliable on-demand logistics engine for delivery. As a result of their growth, they need to grow their data science team to help scale their business. More data scientists help develop and improve the models that power DoorDash’s three-tier marketplace of consumers, merchants, and dashers .

The Data Science Role at DoorDash

DoorDash is aware of the importance of data and the need for a high-energy, confident, and well-experienced data scientist. An existing background in logistics also doesn’t hurt, especially when you have Amazon, Uber, or Lyft on your resume. Additionally after that, any company with marketplace effects.

The general requirements are below:

• Collecting, organizing, processing, and cleaning data using a numerical programming language like SQL, R, Python, or other statistical/scripting tools.
• Analyzing the data using quantitative analysis to provide insights on how to best help business and product leaders understand user behaviors, marketplace dynamics, and market trends.
• Forecast the supply of available dashers as well as incoming delivery demand.
• Build models for next-generation pricing and pay algorithms.
• Predict preparation time for over 50,000 merchant partners.

What are the skills required? DoorDash hires only qualified and experienced candidates with 2+ years of industry experience (4+ years for senior data scientist role) in designing and developing machine learning models with an eye for business impact.

General qualifications include:

• B.S., M.S., or PhD. in Statistics, Math, Computer Science, Physics, Economics, or other related quantitative fields.
• Sound understanding of statistics and machine learning theory.
• Proficiency in numerical programming languages (Python preferable).
• Experience productionizing machine learning models.
• Sound understanding of recommender systems and information retrieval approaches.

What are the types of Data Scientists?

At DoorDash, they have 3 different teams related to data science.

Analytics Data Scientist: This team focus on experimental analysis with emphasis on building dashboards and doing the analysis that supports specific business goals.

Machine Learning Engineers: This team focus on building the bulk of the infrastructure for deploying models.

Data Science Machine Learning: This team sits right in the middle of the former two. They build models that focus on business impact. Their focus is on experimental analysis, building recommendation systems and features, building pipelines for recommendations, designing marketing attribution and segmentation, and building sales models.

Although these three teams are separate and work independently, in some cases, they work very cross-collaboratively.

Check out our guide Machine Learning Interview Questions for example questions and tips.

DoorDash Data Scientist Interview Process

The DoorDash Data Scientist application process is not different from the application processes of most tech companies. The process starts with:

(1) An initial phone screen by a recruiter.

(2) You receive a take-home challenge where you will be graded on your ability to build a machine learning model.

(3) The next step is the take-home challenge review call if you pass the assignment. A data scientist will ask a few questions on how you crafted the solution and go through your thought process.

(4) The last stage is the onsite interview where you will be tested on machine learning, coding, business, and mission values.

Initial screening

After applying for the job, you will get a phone interview with a recruiter. This initial phone call interview by a recruiter usually lasts for 30 minutes. You will be asked a few questions about projects and background related to data science.

• What project(s) have you worked on that demonstrate your skills?
• How would you improve our product?

The DoorDash Take-Home Challenge

Want a preview of the DoorDash take-home challenge? Need a take-home challenge review? We have both at Interview Query .

At this stage, you will be given a take-home problem/dataset via email. This take-home challenge usually takes a few days to complete (48 to 72 hours in most cases) and is crafted depending on which data science role you’ve applied to.

The analytics take-home challenge is divided into two segments. This first part involves analysis on data set (using a case study data provide). The second segment will require you to write SQL queries and answer a few SQL questions .

The data science machine learning take-home challenge is also two parts. The first part requires building a model to** predict delivery duration** while the second part is to create an application that can serve the model from part 1.

Example Questions:

• From the data set given, provide at least one recommendation/insight.
• Outline an experiment you would like to run to test your suggested product/business recommendation.
• State your hypothesis, describe how you would structure your experiment, list your success metrics and describe the implementation.
• Let’s assume that the experiment you ran proved your hypothesis was true. How would you suggest implementing the change on a larger scale? What are some operational challenges you might encounter and how would you mitigate their risk?

Case Study Review

After submitting the take-home problem, depending on if you pass the challenge, you’ll receive a review call (video chat) with a data scientist on the case study given. At this point, you will be asked a series of questions about the techniques used. The interviewer is just trying to get a grasp of your thought process and understand why you made certain decisions.

Onsite Interview and Presentation

The on-site interview lasts for about 5 hours with a lunch break in between. You will be introduced to the data scientist team along with other team members that work closely together.

Here’s what the on-site interview looks like:

• System design, machine learning, and white-board coding
• Object-oriented programming
• SQL queries
• Product metrics and business case study
• Culture fit and behavioral interview

During the on-site interview, you may be given a real-life DoorDash problem to work on and present to the interview panel as various team members pair the program with you. Depending on the type of data science role, expect it to be heavy on either analytics or building a machine learning model. It’s important when presenting at the end to focus on how machine learning affects business problems.

Try answering this interview question asked by DoorDash on Interview Query.

Say you’re running an e-commerce website. You want to get rid of duplicate products that may be listed under different sellers, names, etc… in a very large database.

For example, iPhone X and Apple iPhone 10

How do you go about doing this?

Interview Tips

• Most questions asked in the on-site interview are open-ended. Be ready to come up with a plan/recommendation, and explain in detail to the team, the significance and impact of that recommendation on the company.
• Remember to study and practice many graph traversal techniques and algorithms, and look up and solve problems on Leetcode and Interview Query.
• Practice system design using real projects. Polish your object-oriented programming skills as you may be asked to modify an existing program with OO techniques. Also, read up on Graph traversal with DFS.
• You will also be tested on your communication skills, understanding DoorDash values, and how its business and objectives are unique. Reading up on DoorDash, their current news, products, features, etc., will come in handy.
• DoorDash loves entrepreneur-minded data scientists. Read this blog post on what they’re looking for in many case questions .

Sample DoorDash Data Scientist Interview Questions

Here are some questions asked previously at the DoorDash Data Science interview.

• Code up a stack data structure.
• What is protocol? How does multi-threading work with protocol?
• Find intersecting intervals for two lists of overlapping intervals?
• Give an array of integer, and a start point, and an endpoint print out all the broken intervals. e.g. start = 1, end = 100, array = {2,3,4,6,7}, print {5, 8–100}
• How would you think about pricing delivery fees when launching a new market?

See more DoorDash data scientist interview questions on Interview Query:

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Doordash Data Scientist Salary

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Doordash Data Scientist Jobs

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How to Prepare for a Technical Interview

Kirtan Patel

Kirtan Patel works as a software engineer focusing on Android development for DoorDash’s Ads and Promotions team.

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The technical interview, is a crucial component of the interview loop for software engineers, that gauges the candidate’s ability to perform in the role under consideration. The skills required to successfully complete a technical interview at DoorDash include demonstrable knowledge in data structures and algorithms, and the ability to effectively communicate and problem solve. 

Typically, an experienced engineer takes the role of interviewer, assessing the candidate’s strengths and weaknesses. While the technical interview may seem challenging, it’s important to remember that the interviewer’s honest goal is to find someone who can be a great contributor to a team working on projects that fulfill the company’s business goals.

As a member of a small team of engineers here at DoorDash who contribute to and vet the questions asked in our technical interviews, as well as an active interviewer, I’ll highlight some key pieces of our technical interview. Ultimately, we want excellent candidates who succeed in every part of our interview loop, find a place at DoorDash, and build a highly satisfying career.

Interviews are an attempt to make the best of a difficult situation. In a few short hours we need to figure out if a candidate can successfully contribute to their team and the company over what  might end up being many years. As Lokesh Bisht, the Director of our Customer Analytics team, pointed out in his article on the data science interview , the technical interview is a means to mitigate the cost of bad hires by taking a snapshot of some of the candidate’s skills. Our interview questions need to be well-considered to give an unbiased assessment. 

Interviewers can have different styles and expectations on what they expect to see in a successful candidate. By highlighting the general structure and process of our technical interview, we want to give candidates the best possible preparation for success. 

Data structures and algorithms

Many tech companies stack their interviews with questions related to specific algorithms and data structures, and DoorDash is no different. Candidates should feel comfortable using, as well as understanding, the key differences and applications of the following data structures:

• Directed and undirected
• Cyclic and acyclic
• BST and BT (DAGs)
• Doubly linked lists 
• Single linked lists

This list doesn’t imply other data structures won’t be included in the interview, it just means the ones listed above tend to be more commonly covered. I also highly recommend candidates be well-versed with the worst, best, and average runtime complexities for inserting, removing, and finding elements in all data structures they feel comfortable using. 

Candidates should also be well-versed in the following algorithms:

• Linked lists: being comfortable with manipulating a list and detecting edge cases
• Divide and conquer
• Base case(s) and recursive (inductive) case(s)
• Tail recursion -> not expected, but encouraged
• Dynamic programming solutions to recursive questions (identifying overlapping subproblems and optimal substructure) -> not expected, but encouraged
• Common sorting algorithms (merge, insert, bubble, etc) -> not expected to memorize, but understanding when to use them is recommended
• Binary search
• General comfort in complex searches and sorts in above data structures

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Communication.

The concept of having a communicative approach to solving problems isn’t always emphasized in academic settings. However, we use communication as a metric in determining the success of a candidate due to the importance of teamwork in our engineering organization. Below are some key points to keep in mind.

Keep the interviewer involved

Ideally, we want the candidate to complete the problem and all associated subproblems successfully without any help from the interviewer. However, we encourage candidates to keep the interviewer informed about what they are trying to accomplish. There’s no need for a constant, ongoing conversation, but it is important to describe key decision steps while answering a question. 

Here are some examples:

• “We can use a stack for this solution because...”
• “We can use an in-order tree traversal for this question because…”
• “I may have missed some edge cases, let me take a closer look at my solution.”
• “I can think of a solution in O(N 2 ) time doing X, but I think we can have a linear solution here. I’d like to take a minute to think through an approach.”

I wouldn’t expect a candidate to talk while coding or pseudocoding their solution (in fact, I find it hard to think and talk at the same time, so I prefer silence during those parts of the interview). Candidates should take time to collect their thoughts, but make sure the interviewer is following the process at key points, such as: 

• Clarifying questions after being given the problem 
• The approach to solving the problem
• Identifying potential flaws in the approach
• Changing direction to a new approach  

The interviewer is there to gently guide the candidate to a final solution and to help them score the most points possible for that candidate’s knowledge and skill base.

It’s okay to think

Far too often technical interview tutorials and guides suggest that interviews consider long moments of silence as a negative, and can lead to losing points. There is absolutely nothing wrong with taking time to think about the interview question and in constructing a coherent solution. I’d encourage candidates to take a one or two minute pause in situations which warrant critical thinking. 

Don’t expect constant feedback when solving a problem. An interviewer’s job is to help candidates stay on course toward a working solution, but only if they need it. Generally, candidates will lose points if the interviewer needs to steer them back towards a solution or give them large hints on something they missed. We train our interviewers to only step in when they believe the candidate has a higher chance of scoring better with their intervention. 

Solving the question

Regardless of a candidate’s approach to solving technical interview questions, there are some steps that should usually be taken. 

Remove ambiguity

DoorDash engineers often find themselves solving questions with many unknowns and few clear paths to move forward. The interview process helps us assess this skill in candidates, which is needed to be successful here. We often make questions ambiguous on purpose, and it is the candidate’s responsibility to remove any ambiguity. A candidate may miss edge cases if they don’t clarify the problem. 

In this linked example question , there are a few constraints specifically left out of the question description. If they aren’t accounted for in the solution, there may be some edge cases missed, resulting in a lower score. 

Brute force

In general I advise not to go with a brute force approach as a final solution. In every case where there is an optimal solution with significant complexity improvement, a typical brute force solution will result in a low score for the problem. 

Constructing a solution

A perfect solution doesn’t need to be achieved instantly. Take some time to come up with a general approach and iterate on top of it until it works. I recommend creating a working solution and then running through a test case with the interviewer to find any bugs. We highly value debugging skills, and candidates won’t lose any points if they are able to find their own mistakes and rectify them without interviewer intervention. After coming up with a good solution, candidates can move forward with runtime analysis and follow-up questions (which are very common in our interviews). 

Runtime analysis

Candidates should have a strong understanding of runtime and in-memory complexities for their approach. In general, candidates should be able to clearly explain every step of the solution and why they chose the approach. For example, why use a linked list in a solution instead of an array? 

Unit testing

Although not expected for all questions, some questions will ask candidates to write their own unit tests. Be aware of industry standard testing practices and be able to construct meaningful, yet concise unit tests. Show clear thought and understanding in each unit test, avoiding repetition while still giving confidence to the solution. 

I recommend books such as Clean Code and Code Complete 2 for theoretical knowledge on unit tests as well as other standard software engineering practices. 

Preparation

Preparation is key to tackling the technical interview. The ideal situation for candidates is to find themselves solving a problem very similar to problems they previously solved. 

Consider the following resources:

• Data structure/algorithms practice tools, such as LeetCode
• One-on-one interview preparation tools, such as interviewing.io
• General flow and success in interviews, such as Cracking the Coding Interview

A great way to prepare for the technical interview involves practicing with a friend and on a whiteboard or remotely using a shared screen. Working out a sample problem in this manner will make the actual interview situation more familiar.

In addition to the general success of solving the questions asked, there are three main categories considered when assessing a candidate’s success: 

• Understands common data structures and when to apply them
• Can perform time and space complexity analysis
• Arrives at correct and optimal (in time and space) solution
• Thinks about good abstractions for solving the problem at hand
• Writes well-organized code, with correct syntax, in their language of choice (there is no point difference for choice of language)
• Effectively tests and debugs code
• Asks clarifying questions to eliminate ambiguity
• Explains their thought process when coming up with a solution
• Receives feedback well, without getting overly defensive

Other interviews

While the above focuses on the algorithm/data structure portion of our technical interview, there are other modules of our interview loop. Which modules a candidate encounters depends on the nature and seniority level of the role the candidate is being interviewed for. 

This part of the interview assesses whether a candidate can exemplify our DoorDash values , such as exhibiting a bias for action, getting 1% better every day, and making room at the table. Every candidate goes through this interview, which involves general questions about past challenges and successes, how they would cope with certain theoretical situations, and their career intentions. The candidate will also be afforded the opportunity to ask questions at the end of this interview to assess whether DoorDash feels like a place where they can do some of the best work of their career.

System design

The system design interview is typically given to industry-level, as opposed to entry-level, candidates (L4-plus), and can be a major tool in assessing the candidate’s skill level. It is generally a more difficult interview to practice for. The question assesses a candidate’s ability to build a scalable system with well-thought-out design decisions. These questions are often left intentionally vague and use a real setting. This interview usually gives a deep-dive into one or two specific pieces of the design while taking a shallower glance at the other pieces. 

To prepare, candidates are encouraged to research and reverse engineer common systems within their domain. Frontend candidates, for example, can practice using popular applications such as Gmail or DoorDash. Backend engineers can deep dive into specific areas within large systems such as Twitter or a messenger service.

The backend system design question is often grouped together with domain knowledge, but may also be separated into two rounds depending on which team has the open role. Chao Li, a backend engineer on our Ads and Promotions team, shares his thoughts below: 

“This interview usually focuses on a couple of areas, with increased difficulty levels:

• The first part, which most candidates can get through with little difficulty, involves a breakdown of the problem requirements and suggesting basic components. This area requires steps such as understanding the problem statement, translating requirements into technical components, breaking down the data model, suggesting an API, and coming up with a database schema.
• Candidates should be prepared to dive deep into each component and talk about how different situations are handled. Typical examples include how a payment component handles double writes, or how a distributed queue handles surges and failures.
• Be ready to discuss details about their approach. For example, if a candidate mentioned using a message queue to solve the problem, we would expect justification for why a message queue is the best solution, what are the trade-offs for the specific product versus other products (i.e., AWS Kinesis over an on-premises Kafka cluster), what were some other potential solutions, what are the pros and cons, and what are the failure scenarios for this solution. 
• The last part of this interview concerns scalability. We assess whether a candidate knows how to get from zero to a 1x solution, as well as a 1x to a 10x solution. In particular, the candidate should be able to suggest how the tech stack and architecture will need to evolve to achieve scale.“

The iOS interview, commonly referred to as the architecture interview, will dive into application design, which will later be implemented in a coding round. Tom Taylor, an engineer on DoorDash’s iOS platform team, shares his thoughts below:

“During the architectural interview, candidates are given a feature and design and expected to whiteboard an iOS system. No coding is required for this interview; we mainly talk about elements at a class, struct, or interface level. While we do not require every candidate to be expert software architects, it is important when designing a feature to consider testing, scalability, data flow, and techniques for managing code when working on a larger codebase. Also, candidates should understand how to design a system without relying on third-party libraries.”

The Android interview usually involves a dedicated portion to go over system design. As preparation, we recommend going through some common apps and being able to give a deep dive into, or reverse engineer, them. The question may not be to design an app doing a specific task, but could also involve designing a library that an app may use. For example, candidates may be asked to design an image loading library similar to Glide . 

It’s important to have strong fundamentals, such as threading, caching, memory and battery consumption, network usage, scalability, app persistence, and interaction with the operating system to succeed in this interview.

This interview will typically go through developing a web application. Michael Sitter, tech lead for DoorDash’s Web Platform team, shares his thoughts below:

“We don't expect candidates to necessarily be able to describe solutions for scalability and fault tolerance, but the best candidates are able to include those qualities in their designs. Instead, we try to focus on things like the contracts between the web/client applications and the backend APIs. What data do we need to collect? How should the client app respond to various API responses? Synchronous or asynchronous? How do we handle cases where we have high or low latency?”

“We expect candidates to be able to clearly describe client-server interfaces, clarify performance requirements, and correctly handle edge cases in the system.” 

Domain knowledge

The domain knowledge interviews test the candidate’s fundamentals in the platform they are applying for. They should be comfortable with basic terminology and applications within the given domain as well as demonstrate a strong understanding of the infrastructure they are using. This interview involves a deep dive into an example project in the domain area. We usually conduct this interview in a question-and-answer format, and it is occasionally combined with the system design interview. iOS candidates normally don’t go through this interview in their loop, as it is replaced with a debugging round explained in the Coding section below. 

Some interview loops contain a coding round. This module usually follows a take-home project involving a real-world application and will ask the candidate to add or change a feature within their already built application. This interview is used to assess a candidate's proficiency in the language and platform they are working in as well as how they architect their code. 

The iOS interview loop differs slightly from other platforms. Candidates will forgo the domain knowledge and coding interviews described above and instead go through two modified coding rounds. In the first round, the candidate will implement the design they have built in the system design/architecture interview. During the second round, they will receive an application in xCode with some errors and flaws, and are expected to debug the codebase into a working solution. 

There is also no take-home project during iOS interviews. Instead, we ask candidates to participate in a technical phone screen where they will work with an iOS engineer in finishing a partially completed application. This module is done prior to any on-site interviews. 

Interviewing can be an unnerving and sometimes challenging experience, but it gets much easier through repetition and practice. Along with a skill evaluation, however, candidates also get a chance to see how their prospective colleagues think and communicate as well as a glimpse into the types of problems we solve at DoorDash. 

I hope to provide ample preparation materials in order to mitigate against some of the biases that come with interviewing and to let the process highlight the prospective connection between the interviewee and the company. I wish nothing but success to any future candidates and I hope we can be a great environment for candidates to advance their careers.  

If you are interested in building a logistics platform that supports local economies, consider joining our team !

Header photo by Fotis Fotopoulos on Unsplash .

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Supreme Court to hear biggest homeless rights case in decades. What both sides say.

Laura Gutowski's husband always made her feel trapped.

The lifelong homemaker said her husband of more than 30 years never let her get a job in Grants Pass, Oregon , the small city surrounded by mountains where they lived, an hour north of the California border.

She shared a seven-bedroom home with her husband's family, but when he died three years ago, she was told to leave, Gutowski told USA TODAY. Gutowski, now 55, was left with only $120. First, she lived in her Chevrolet Cavalier, then briefly at a shelter that shuttered 16 months after launching.

Now Gutowski, who uses a walker, lives in a tent and sleeps on a cot under five layers of blankets in Morrison Centennial Park, about a mile and a half from the house she lived in most of her life. She has lymphedema, diabetes, high blood pressure and kidney disease, and this summer she might face more challenges living without a house.

Grants Pass, a city of about 40,000, is at the center of a Supreme Court fight pitting the unhoused community against local officials, who say they want control of their parks back. The Supreme Court could have a deep impact on Gutowski and about 600 others who live outdoors when the judges on Monday hear arguments in a case about whether the city can enforce a ban on camping and sleeping at all times, in all public spaces.

"I don't like having to try to survive out here. It's not comfortable and it's not warm," Gutowski said during a recent phone interview.

Homeless advocates argue the U.S. Constitution's Eighth Amendment protects people from being punished based on a personal status outside their control − like being homeless, according to David Peery , a lawyer with the National Coalition for the Homeless. If Grants Pass wins the case, he said, homeless residents could face punishment for using as little as one blanket outside, in addition to any tent or other covering.

"This is the biggest human rights case you've never heard of," Peery said.

City leaders await Supreme Court hearing

City leaders in the Ninth Circuit, which includes Alaska, Arizona, California, Hawaii, Idaho, Montana, Nevada, Oregon and Washington, are watching closely as the hearing approaches. Lawyers representing each side say the court's decision would impact a large chunk of the country's unsheltered homeless population , either protecting them from criminalization or giving local authorities more leeway to permanently prevent sleeping in public.

If the court sides with the unhoused community in Grants Pass, cities and states across the U.S. that have similar 24-hour bans on sleeping in public will be unable to enforce them, legal experts told USA TODAY. If the court sides with Grants Pass, authorities in the Ninth Circuit can start ticketing and arresting people for sleeping outside.

National attention surrounding the case has increased stigma in Grants Pass, Gutowski said. These days, more residents − including children in the park − hurl nasty words her way.

"It wasn't that long ago that I was a part of that same community that is now looking at all of us and thinking we're the lowest scum of the Earth, that we should just be wiped off or bused out of the city," she said.

FLORIDA Gov. DeSantis signs bill banning homeless from camping in public spaces

Like across the country, nonprofit food and health care providers and religious groups form a small but mighty stopgap for the unhoused in Grants Pass. Volunteers serve hot food and a nonprofit, Mobile Integrative Navigation Team , provides free transportation to much-needed medical care. But without housing or shelter, people remain living outdoors.

For the past three years, elected officials in Grants Pass have tried to create an appropriate shelter space, but nothing has worked, Mayor Sara Bristol told USA TODAY.

"We need to help establish a place where people can legally sleep, and it's been a real uphill battle with all kinds of different challenges," she said.

What is the Grants Pass ruling about?

In this case, Grants Pass says it needs to be able to clear residents like Gutowski out of parks. But the city hasn't been able to enforce its around-the-clock camping ban on public property.

That's because a 2022 U.S. Court of Appeals for the Ninth Circuit decision ruled homeless people in places without enough shelter beds have an Eighth Amendment right not to face punishment for living outside and protecting themselves from the elements. In Grants Pass, that has meant tents, tarps and other belongings dot parks while public benches and picnic tables are often used for sleeping.

Authorities have been enforcing an ordinance that prevents people from setting up their tents in the same spot indefinitely, Bristol told USA TODAY. But lawyers handling the city's case say that's not adequate.

Appeals court decisions have "limited the ability of towns and cities, large and small, to address this crisis and have taken away the ability to really address what's happening in our communities," said Theane Evangelis, one of the lawyers arguing the case for Grants Pass.

Homeless rights advocates say the enforcement city leaders want will only make the country's homeless crisis worse, having dire consequences for unhoused populations where people from marginalized communities are overrepresented.

Some legal historians also argue the Supreme Court should not overlook the history of anti-camping bans, including vagrancy laws that served to bar people from certain spaces based on their race. In the 1800s, vagrancy laws in many parts of the U.S. largely targeted formerly enslaved people.

"That is our legacy, this desire to purge undesirable people from communities, to drive people out," said Sara Rankin, a law professor at Seattle University, and author of The Wrong Side of History, a study tracing the origins of anti-camping laws.

LIVING OUTDOORS A homeless man living on national forest land was shot by federal police. He's now suing

Where are homeless residents allowed to go?

In the West, cities like Denver , Los Angeles , Portland , Oregon, and San Diego , can offer homeless people spots in new hotel programs and sanctioned campsites to clear away encampments.

But unlike those big cities, Grants Pass doesn't have the same forms of assistance to offer unhoused residents, Evangelis said.

There is no city-run shelter, only a church-run program for homeless people that includes a shelter that requires residents to work. Transitional housing, in the form of a tiny home village, opened in 2021, but there are only 17 slots. Due to a severe lack of affordable housing in Grants Pass, turnover at the facility is low, service providers said.

"The city has no way to limit encampments, and it has no way to encourage people to accept services and to find a place indoors," Evangelis said.

Why does Grants Pass want to ban blankets, pillows, cardboard?

A 24-hour ban would give the city authority to clean up all encampments, said Judge Glock, director of research at the Manhattan Institute , a think tank supporting individual freedom and the rule of law.

"The main reason they should clear these encampments, even in the nighttime hours, is that these spaces aren't fit for human habitation," said Glock, who along with other researchers filed an amicus brief in support of Grants Pass. "A lot of these encampments are an incredible danger to the homeless themselves."

If the city wins the Supreme Court case, Glock said, it should build more homeless shelters so that its unhoused residents have somewhere to go.

But in her first year in office, Bristol and city council members tried to launch a sanctioned campsite so that unhoused people could put their tents somewhere that wasn't a park. But the plan went sideways and transformed into an effort to purchase a building for an indoor shelter, she said.

That idea fell apart, Bristol said, when in late 2022 Grants Pass residents pushed back, saying the site was too centrally located. It also would have been right across from a children's dance studio, said Ruth Sears, the studio building owner.

"For the most part, we were compassionate and recognized something needed to be done to help people in need, but that was a terrible location and would have impacted so many," Sears, 72, told USA TODAY.

As of this year, there is no shelter where someone living outdoors can go at night, and no money left for the city to fund any more plans, Bristol said.

The lack of shelter means that if the Supreme Court sides with Grants Pass, there wouldn't be any places in town − indoors or outdoors − where an unhoused person could legally sleep, said Gutowski.

"Where are all these people going to go? There are no other shelters," Gutowski said. "I’m worried about them leaving the city and going up into the mountains."

Homeless advocates warn against criminalization

National homeless rights advocates have decried the sweeping camping ban Grants Pass wants to enforce, arguing punitive measures work against efforts to end homelessness. More affordable housing and assistance with health care will help homeless people, not laws banning sleeping outside, said Ann Oliva, CEO of the National Alliance to End Homelessness.

"As communities address the homelessness crisis, they must follow the evidence of what works best − providing immediate help by connecting people to low-barrier shelter and services, while the long-term affordable housing and services are put in place," she said.

An arrest record stemming from a camping ban would make it harder for someone to secure a job or housing, making it more likely they'd end up in jail repeatedly, said Samantha Batko, a researcher at the Urban Institute who studies city budgets.

"Criminalization doesn't solve homelessness," she said. "What happens is, this cycle of arrests and citations get people caught in a homelessness-jail cycle."

Evangelis said the 24-hour camping ban has come as a last resort.

"This is just the bread and butter of running a city," she said, adding that concerns from advocates about increased criminalization of unhoused people are "unfounded."

"They want to be just like cities outside of the Ninth Circuit who have all of the tools available," she said of Grants Pass.

Ed Johnson, a public defender in Grants Pass, first took on the case after learning unhoused people were receiving camping fines they couldn't pay. Fines are also a huge burden to homeless people, said Johnson, who is not related to the named plaintiff in the case, Gloria Johnson.

City advocates, however, say they're necessary.

"Whatever the dangers of a fine − those can be a danger for some people out there − they pale in comparison to the danger they are facing in the encampments," Glock said.

Across the country, statistics also show people of color are more likely to become homeless than their white counterparts, due to systemic racial and housing discrimination, Johnson said.

Last year, Black people made up 13% of the U.S. population, but accounted for 37% of all homeless people, according to the U.S. Department of Housing and Urban Development . In 2023 there was also a 40% and 28% increase in the number of Asians and Latinos, respectively, experiencing homelessness.

Peery, who is Black , briefly ended up behind bars after a Miami landlord evicted him when he got laid off during the Great Recession in 2008. He was homeless for the next 10 years.

"Aside from the fact that it takes you away from where you're at and scatters you, the hit to your psyche just sends you into a fog," Peery said, adding, "there's a huge racial equity component to this."

For Rankin, anti-camping laws that prohibit tents and bedding are the latest version of vagrancy laws.

"That instinct that lives on is about punishing unemployment," she said, describing how going back centuries, elected leaders and other officials have used criminalization to rid cities of homeless people perceived to be "economic threats."

When was the last time SCOTUS heard a homeless case?

It has been decades since the Supreme Court heard a case that could criminalize those experiencing homelessness.

In 1972, the Supreme Court overturned a Jacksonville, Florida, law prohibiting vagrancy. The law banned begging and applied to people who slept during the day and wandered at night, the Florida Times-Union, part of the USA TODAY Network, reported.

The ruling in Papachristou v. Jacksonville said the city's anti-vagrancy ordinance, which led to hundreds of arrests , made it too easy for authorities to criminalize activities that are "normally innocent."

Across the country, states and cities outside the Ninth Circuit have in recent years passed more camping bans, to respond to growing unsheltered populations and encampments that block sidewalks and other public spaces.

In Supreme Court documents, lawyers representing homeless residents said most cities with anti-camping ordinances don't go as far as the ordinance in Grants Pass.

Out of 200 cities with populations similar to that of Grants Pass, more than 80% do not ban sleeping on all public property, at all times, according to amicus briefs. In most other cities, bans are in place with exceptions, like allowing camping when there are no shelter beds available.

"Whatever their merits as a matter of public policy, such laws do not punish the status of homelessness in the way that the" Grants Pass ordinance does, lawyers wrote.

No matter what happens in late June, there will still be hundreds of homeless people living outdoors in Grants Pass, Gutowski said.

At that point, care teams will still be helping, reminding the people in tents that they matter, she said.

"They're our angels. They truly are," Gutowski said. "Not everybody realizes that, but the ones that help, we wouldn't be here if it wasn't for them."