Instacart Interview Questions — Page 9

Instacart·Data Scientist·Take-home Assignment

Jun 2026

Instacart data science case that went deep fast. The whole thing was one big open-ended prompt that tied SQL output into budget strategy, experiment design, and segmentation analysis. More like a consulting case than a typical DS interview.

Using findings from a SQL analysis on advertiser spend and program profitability, propose a concrete budget allocation for next quarter that maximizes net profit while managing risk. Your answer should cover recommended program-level budget shares, advertiser-level allocation rules, and a back-of-the-envelope incremental profit estimate with stated assumptions.
Design an experiment to validate the proposed budget allocation strategy. Specify your randomization unit, power and sample size considerations, primary KPI, and guardrails. Define what success looks like and how you would make a go/no-go decision.
Walk through your analysis plan: what segmentations would you run, how would you handle seasonality and regression to the mean, what additional data would you request, and what confounders are you worried about and how would you address them?

“This part took me way longer than I expected.”

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Instacart·Data Scientist·Onsite - Product Sense / Strategy

Jun 2026

Instacart data scientist interview that was basically a full product case study compressed into one question. They handed me this sprawling 'improve shopper retention' prompt and expected the whole lifecycle from problem definition to post-launch review. More PM-flavored than I expected for a DS role.

You've been given a vague mandate to improve shopper retention. Walk through how you'd take it from initial idea all the way to launch, covering problem definition, success metrics, guardrails, discovery, PRD structure, stakeholder mapping, milestones, and kill criteria.
How would you de-risk the initiative using a prototype before committing full resources?
How would you manage cross-functional change with teams like CX, Legal, and Sales during this initiative?
Walk me through a 30/60/90-day plan for this initiative.
Describe a tough trade-off you'd make on this project and defend it.

“This question is enormous and I underestimated how long it would take to just get through the problem definition piece before they'd start probing.”

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Instacart·Software Engineer·Technical Phone Screen

Jun 2026

Instacart system design screen, focused on worker management. Pretty straightforward premise but the details got tricky fast.

Design a method to add a worker to the system, where each worker has a unique ID, a title, and a salary. The system should support future queries and updates on this data.

“Seemed simple at first and I jumped straight to schema design without asking about scale or access patterns.”

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Instacart·Software Engineer·Technical Phone Screen

Jun 2026

Instacart coding screen for a software engineer role. The problem looked deceptively simple at first glance but there's a lot of edge-case territory once you start thinking about variable resolution order.

Build an expression evaluator that processes a sequence of variable assignment statements. Each variable can be assigned a literal number, another variable, or a simple arithmetic expression (add, subtract, multiply, divide) using variables and numbers. After all statements are processed, return the resolved value of each variable.

“My first instinct was to just parse line by line and store values in a map, which works fine until you realize variables can reference other variables and you need to trace back through the chain.”

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Instacart·Product Manager·Onsite - Product Sense / Strategy

Jun 2026

Instacart product sense interview, one question about designing a demand forecasting dashboard for shoppers. Pretty open-ended and I wasn't totally sure how deep to go on the technical side versus the product side.

How would you design a dashboard for Instacart to predict and manage shopper demand?

“I spent too long on the metrics layer and not enough time thinking about who actually uses this dashboard.”

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Instacart·Software Engineer·Technical Phone Screen

Jun 2026

Instacart coding screen with a concurrency-flavored design problem. Not what I expected from a product company but the problem was actually pretty interesting once I stopped panicking.

Design a promotion system where an employee's title and salary can be updated, but if they're currently in the office, the promotion should be queued and applied the next time they leave and re-enter. If multiple promotions are queued, only the most recent one should take effect.

“I spent the first few minutes trying to figure out if this was a system design question or a coding question and kind of wasted that time.”

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Instacart·Software Engineer·Technical Phone Screen

Jun 2026

Instacart software engineer interview with a coding problem that's basically a boarding simulator, broken into four parts across the session. More design and tradeoff discussion than I expected for what looked like a straightforward queue problem.

Given a waiting line of people and a bus with limited capacity, implement a boarding function that boards priority riders before non-priority riders while preserving relative arrival order within each group. Return who boarded and who's still waiting.
Walk through the tradeoffs in your boarding implementation. What's an alternative approach, how do they compare on time and space complexity, and what would you change if this were going into production?
Write unit tests for the boarding logic. What edge cases would you cover?
Extend your solution to handle wheelchair riders: the bus can carry at most 2 wheelchair users, each consuming a variable number of capacity units. Priority boarding and stable ordering still apply.

“Spent too long second-guessing whether to use a stable sort or just partition.”

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Instacart·Software Engineer·Technical Phone Screen

Jun 2026

Coding round at Instacart for a software engineer role. The problem looked like a simple variable evaluation exercise until the recursive references showed up and things got messier fast.

You're given a target variable and a list of assignment strings like 'Ti = expression', where each expression is a number, a single variable, or simple arithmetic over variables and numbers. Compute the numeric value of the target variable. Then extend the solution to handle recursive variable references, and detect cycles or unresolvable references.

“Started fine with the base case, just parse the string and evaluate.”

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Instacart·Software Engineer·Onsite - Coding / Algorithms

Jun 2026

Coding round at Instacart for a software engineer role. One problem, solved it, moved on.

Given a set of constraints, find the minimum number of shoppers needed to fulfill orders.

“Binary search was the key insight here.”

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Instacart·Software Engineer·Technical Phone Screen

Jun 2026

Instacart software engineer interview that was basically one big file-parsing problem broken into layers. The core question was straightforward but the trade-offs discussion is where things got real.

You have a file containing a matrix. Given a target row and column, return the value at that position.
Extend your solution so the file contains multiple named matrices, each with a header key. Given a list of (key, row, col) queries, return the correct value from the matching matrix for each query.
Walk through the trade-offs between three file-reading strategies: loading the whole file into memory, processing it line by line, and using file pointer seeks with a fixed-size buffer for very large files.

“Part one felt easy enough.”

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