Type · conflict resolution

How to Pass the Dept Software Engineer Interview in 2026
The Dept DNA (TL;DR)
The Dept Interview Loop
Your onsite loop will typically consist of 5 rounds.
- 1
Round 1
Recruiter ScreenMotivation, role fit, logistics. - 2
Round 2
Coding ScreenLeetCode-medium algorithmic problems under time pressure. - 3
Round 3
System DesignDistributed systems, trade-offs at scale, architecture under constraints. - 4
Round 4
Onsite CodingLeetCode-hard, debugging, code clarity, edge cases. - 5
Round 5
Behavioral / LeadershipPast evidence of ownership, influence, resolving conflict.
The Danger Zone: Top Reasons Candidates Fail
Based on our database of Dept interview outcomes, avoid these common traps:
- Not addressing latency requirements for real-time recommendations.
- Inefficiently iterating through all possible windows for each user.
- Not testing with diverse user interaction scenarios.
- Not articulating the impact or lessons learned.
Get the full Dept playbook, free
Every round, the exact grading rubric interviewers score against, all the questions, and unlimited mock-interview practice. Free account, no credit card.
Test Yourself: Real Dept Questions
Three real prompts pulled from our database.
Type · motivation
Type · architecture
+ many more questions, signals, and worked examples
Sign up to unlock the full Dept grading rubric
Dept Interview Question Bank
A sample from our database, grouped by round. Sign up to see the full set.
9 of 14 questions shown
Recruiter Screen
1- 1
Type · motivation
What interests you about working at Dept, specifically within the advertising technology space?
Coding Screen
3- 2
Type · algorithmic
Given a list of user IDs and their corresponding ad impression timestamps, write a function to find users who had more than N impressions within a M-minute window. Assume timestamps are sorted. - 3
Type · algorithmic
You are given a stream of ad click events, each with a campaign ID and a timestamp. Design a data structure to efficiently retrieve the top K most frequent campaign IDs within the last hour. - + 1 more questions in this round (sign up to unlock)
System Design
3- 4
Type · architecture
Design a system to serve personalized ad recommendations to millions of users in real-time. Consider data ingestion, user profiling, model serving, and ad selection. - 5
Type · architecture
How would you design a distributed rate limiter for an ad bidding API that needs to handle billions of requests per day while ensuring fair usage across different advertisers? - + 1 more questions in this round (sign up to unlock)
Onsite Coding
3- 6
Type · algorithmic
Implement a function to find the longest common subsequence between two strings representing user search queries. Optimize for performance. - 7
Type · debugging
Here is a piece of code that calculates user engagement scores based on various interactions. There's a subtle bug causing scores to be inaccurate for users with specific interaction patterns. Find and fix it. - + 1 more questions in this round (sign up to unlock)
Behavioral / Leadership
4- 8
Type · ownership
Tell me about a time you encountered a significant technical challenge in a project. How did you take ownership to overcome it, and what was the outcome? - 9
Type · collaboration
Describe a situation where you had a technical disagreement with a colleague or manager. How did you approach the discussion, and what was the resolution? - + 2 more questions in this round (sign up to unlock)
Unlock all 14 Dept questions, free
No credit card. Every question with its framework, the grading signals interviewers score against, and a worked answer for each.
Interview tracks at Dept
How Dept's DNA translates across functions. Pick your role.
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Practice Dept interviews end-to-end
Dept Mock Interview
Run a live mock interview with our AI interviewer using Dept-style prompts. Get scored on structure, signal, and answer length - exactly how the real loop grades you.
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STAR Stories for Dept Behavioral Rounds
Build a Story Bank of your past wins, mapped to the leadership signals Dept interviewers grade on. Reuse them across every behavioral round.
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Dept Interview Prep Hub
The frameworks behind every Dept round: CIRCLES for product sense, hypothesis-driven debugging for analytical, STAR for behavioral. Learn each one in 10 minutes.
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Interview Frameworks
CIRCLES, STAR, AARRR, RICE, MECE. The exact frameworks that make Dept interviewers nod instead of frown. Step-by-step playbooks with the moves and the pitfalls.
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Sample answers
What a strong answer to these Dept interview questions shows.
Tell me about a time you had a significant disagreement with a colleague or manager. How did you approach the situation, and what was the resolution?
A strong answer shows: Calm and objective description of the conflict.; Focus on finding a resolution rather than 'winning' the argument.; Demonstration of empathy and active listening..
What interests you about working at Dept, specifically within the advertising technology space?
A strong answer shows: Enthusiasm for Dept's work in advertising.; Understanding of Dept's business model or clients.; Articulates specific reasons for wanting to join..