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Growth · Software Engineer Interview Guide

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How to Pass the Shopfully Software Engineer Interview in 2026

The Shopfully DNA (TL;DR)

The Shopfully app's core mission to connect shoppers with local offers drives the interview focus. They grade execution ability, especially how candidates can directly impact user engagement with digital flyers and retailer ROI, often through a practical case study.

The Shopfully Interview Loop

Your onsite loop will typically consist of 5 rounds.

  1. 1

    Round 1

    Recruiter Screen
    Motivation, role fit, logistics.
  2. 2

    Round 2

    Coding Screen
    LeetCode-medium algorithmic problems under time pressure.
  3. 3

    Round 3

    System Design
    Distributed systems, trade-offs at scale, architecture under constraints.
  4. 4

    Round 4

    Onsite Coding
    LeetCode-hard, debugging, code clarity, edge cases.
  5. 5

    Round 5

    Behavioral / Leadership
    Past evidence of ownership, influence, resolving conflict.

The Danger Zone: Top Reasons Candidates Fail

Based on our database of Shopfully interview outcomes, avoid these common traps:

  • Describing a situation where they simply told people what to do.
  • Using inappropriate data structures that lead to high memory or slow query times.
  • Introducing new bugs while refactoring.
  • Insufficiently robust traffic splitting mechanisms leading to biased results.

Test Yourself: Real Shopfully Questions

Three real prompts pulled from our database.

Type · Influence

Describe a time you had to influence a difficult stakeholder (internal or external) to adopt your recommendation. How did you approach it, and what was the result?

Type · debugging

A dashboard displaying daily active users (DAU) for different ad campaigns has suddenly started showing incorrect, fluctuating numbers. The backend service aggregates data from multiple sources. How would you approach debugging this issue?

Type · algorithmic

Implement a rate limiter for API requests to Shopfully's ad serving endpoint. The limiter should ensure that no more than N requests per user are allowed within a T second window. Consider distributed systems if the service scales across multiple machines.

+ many more questions, signals, and worked examples

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Shopfully Interview Question Bank

A sample from our database, grouped by round. Sign up to see the full set.

9 of 23 questions shown

1

Recruiter Screen

1
  1. 1

    Type · motivation

    What interests you about working at Shopfully, specifically within our advertising and growth teams?
2

Coding Screen

3
  1. 2

    Type · algorithmic

    Given a stream of user ad impression events (timestamp, user_id, ad_id, click_flag), design an algorithm to calculate the click-through rate (CTR) for each ad in near real-time. Consider memory constraints and potential for high volume.
  2. 3

    Type · algorithmic

    Implement a function that takes a list of user segments (defined by a set of properties like 'age', 'location', 'device_type') and a list of ad campaigns (each with targeting criteria). The function should return which campaigns a given user would be eligible for. Assume segments and targeting criteria are represented as dictionaries or JSON objects.
  3. + 1 more questions in this round (sign up to unlock)
3

System Design

3
  1. 4

    Type · system-design

    Design a system to detect and prevent ad fraud (e.g., click farms, bot traffic) in real-time for a high-volume ad network. Consider data ingestion, feature extraction, model serving, and actioning.
  2. 5

    Type · system-design

    Design an A/B testing framework for evaluating new ad creatives or targeting strategies on Shopfully's platform. The system should handle traffic splitting, metric collection, and result analysis.
  3. + 1 more questions in this round (sign up to unlock)
4

Onsite Coding

3
  1. 6

    Type · algorithmic

    You are given a large dataset of user interactions with ads (view, click, conversion). Design a data structure and algorithm to efficiently answer queries like: 'What is the conversion rate for ad X among users who clicked on ad Y within the last 24 hours?'
  2. 7

    Type · code-clarity

    Refactor the following Python code snippet, which calculates the effective cost per mille (eCPM) for ad campaigns, to improve its readability, maintainability, and efficiency. Pay attention to variable naming, error handling, and potential edge cases.
  3. + 1 more questions in this round (sign up to unlock)
5

Behavioral / Leadership

13
  1. 8

    Type · conflict resolution

    Tell me about a time you had a significant disagreement with a cross-functional team member (e.g., engineering, marketing) about a product decision. How did you approach the situation, and what was the outcome?
  2. 9

    Type · Ownership

    Tell me about a time you took ownership of a problem that wasn't directly your responsibility. What was the situation, and what did you do?
  3. + 11 more questions in this round (sign up to unlock)

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Interview tracks at Shopfully

How Shopfully's DNA translates across functions. Pick your role.

Compare Shopfully with similar employers

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