Type · architecture
Design a system to track and attribute conversions for online advertising campaigns across multiple channels (e.g., search, social, display). How would you handle cross-device tracking and potential view-through conversions?
How to Pass the Caffeina Software Engineer Interview in 2026
The Caffeina DNA (TL;DR)
Caffeina's "Ideas Never Sleep" ethos drives their assessment of candidates who can transform creative concepts into tangible "Digital Product" or "Digital Media" solutions. They look for individuals who demonstrate a clear understanding of market impact and can articulate how their contributions align with client goals.
The Caffeina 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 Caffeina interview outcomes, avoid these common traps:
- Blaming the other party entirely without taking any responsibility.
- Poorly structured code making it hard to modify or optimize.
- Focusing only on the fix without discussing diagnosis or prevention.
- Not considering potential division by zero or invalid inputs.
Get the full Caffeina 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 Caffeina Questions
Three real prompts pulled from our database.
Type · conflict resolution
Tell me about a time you had a significant disagreement with a team member or manager. How did you approach the situation, and what was the resolution?
Type · conflict-resolution
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 outcome?
+ many more questions, signals, and worked examples
Sign up to unlock the full Caffeina grading rubric
Caffeina Interview Question Bank
A sample from our database, grouped by round. Sign up to see the full set.
9 of 18 questions shown
1
Recruiter Screen
1- 1
Type · motivation
What interests you about working at Caffeina, specifically within our advertising technology domain, and how do you see your skills contributing to our mission of driving measurable growth for clients?
2
Coding Screen
3- 2
Type · algorithmic
Given a list of user segments and their associated bid values for advertising campaigns, write a function to find the optimal allocation of a fixed budget across these segments to maximize total bid value. Assume segments are independent. - 3
Type · algorithmic
Implement a rate limiter for ad impressions. Given a user ID, timestamp, and a maximum number of impressions allowed per user within a time window (e.g., 100 impressions per minute), determine if an impression should be allowed. - + 1 more questions in this round (sign up to unlock)
3
System Design
3- 4
Type · architecture
Design a real-time bidding (RTB) system for ad impressions. Consider the components involved, data flow, latency requirements, and how to handle millions of bid requests per second. - 5
Type · architecture
Design a system to track and attribute conversions for online advertising campaigns across multiple channels (e.g., search, social, display). How would you handle cross-device tracking and potential view-through conversions? - + 1 more questions in this round (sign up to unlock)
4
Onsite Coding
3- 6
Type · algorithmic
You are given a stream of ad campaign performance data, where each data point includes campaign ID, timestamp, and a performance metric (e.g., clicks, impressions). Design an algorithm to detect anomalous spikes or drops in performance for any given campaign in near real-time. - 7
Type · algorithmic
Implement a function to calculate the effective cost per mille (eCPM) for ad inventory. This involves considering various factors like bid price, ad format, user demographics, and conversion probability. The function should be highly optimized for frequent calls. - + 1 more questions in this round (sign up to unlock)
5
Behavioral / Leadership
8- 8
Type · conflict-resolution
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 outcome? - 9
Type · ownership
Tell me about a time you encountered a significant technical challenge or bug in a production system that was impacting clients. What steps did you take to diagnose, fix, and prevent recurrence? - + 6 more questions in this round (sign up to unlock)
Unlock all 18 Caffeina 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 Caffeina
How Caffeina's DNA translates across functions. Pick your role.
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Practice Caffeina interviews end-to-end
Caffeina Mock Interview
Run a live mock interview with our AI interviewer using Caffeina-style prompts. Get scored on structure, signal, and answer length - exactly how the real loop grades you.
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STAR Stories for Caffeina Behavioral Rounds
Build a Story Bank of your past wins, mapped to the leadership signals Caffeina interviewers grade on. Reuse them across every behavioral round.
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Caffeina Interview Prep Hub
The frameworks behind every Caffeina 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 Caffeina 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 Caffeina interview questions shows.
Design a system to track and attribute conversions for online advertising campaigns across multiple channels (e.g., search, social, display). How would you handle cross-device tracking and potential view-through conversions?
A strong answer shows: Knowledge of different attribution models (first-click, last-click, linear, time-decay, data-driven).; Strategies for user identification and cross-device tracking (e.g., probabilistic matching, logged-in user IDs).; Data pipeline design for collecting and processing conversion events.; Consideration for privacy regulations (e.g., GDPR, CCPA)..
Tell me about a time you had a significant disagreement with a team member or manager. How did you approach the situation, and what was the resolution?
A strong answer shows: Constructive approach to conflict.; Ability to communicate respectfully during disagreements.; Focus on resolution and maintaining relationships..
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