Type · Market Sizing
Estimate the total addressable market (TAM) for business travel booking solutions in Europe.
How to Pass the Duffel Product Manager Interview in 2026
Growth · Product Manager Interview Guide
Sign up to see ATSHeadquartered in United KingdomInterview language: English
The Duffel DNA (TL;DR)
Duffel's core focus on simplifying travel APIs means interviews probe for your ability to tackle complex domains like "Flights Build" and "Search Book Ancillaries Order". They assess your capacity for structured problem deconstruction and delivering robust, scalable solutions, often through detailed discussions of technical decisions.
The Duffel Interview Loop
Your onsite loop will typically consist of 5 rounds.
- 1
Round 1
Recruiter ScreenMotivation, basic fit, logistics. - 2
Round 2
Product Sense / DesignCustomer empathy, creativity, structured design thinking. - 3
Round 3
Analytical / ExecutionMetrics definition, root-cause debugging, A/B testing. - 4
Round 4
Strategy / EstimationMarket sizing, competitive positioning, business trade-offs. - 5
Round 5
Behavioral / LeadershipPast evidence of ownership, influence, resolving conflict.
The Danger Zone: Top Reasons Candidates Fail
Based on our database of Duffel interview outcomes, avoid these common traps:
- Not having a clear framework for prioritization.
- Not considering how to integrate policy data effectively.
- Misinterpreting statistical significance (e.g., concluding B is worse).
- Failing to consider potential negative impacts (e.g., increased load times).
Test Yourself: Real Duffel Questions
Three real prompts pulled from our database.
Type · Influence
Tell me about a time you had to influence a senior stakeholder or a team that didn't report to you to adopt your product vision or strategy. What was your approach?
Type · Product Strategy
How would you think about building a feature to help business travelers find the most cost-effective flight options while still meeting their travel policy requirements?
+ many more questions, signals, and worked examples
Sign up to unlock the full Duffel grading rubric
Duffel Interview Question Bank
A sample from our database, grouped by round. Sign up to see the full set.
9 of 14 questions shown
1
Recruiter Screen
1- 1
Type · Motivation
Why are you interested in Duffel, and what specifically about our mission and the travel industry excites you?
2
Product Sense / Design
3- 2
Type · Product Design
Imagine Duffel wants to expand into offering ancillary services (e.g., seat selection, baggage, lounge access) directly within our flight booking flow. How would you approach designing this feature? - 3
Type · Product Improvement
Duffel currently allows users to search and book flights. What's one key area where you think we could significantly improve the user experience, and how would you measure the impact of that improvement? - + 1 more questions in this round (sign up to unlock)
3
Analytical / Execution
4- 4
Type · Metrics Definition
We've launched a new feature that allows users to save their frequent flyer numbers. What are the key metrics you would track to determine its success? - 5
Type · Root Cause Analysis
Bookings through Duffel have unexpectedly dropped by 15% this week. How would you investigate this issue? - + 2 more questions in this round (sign up to unlock)
4
Strategy / Estimation
3- 6
Type · Market Sizing
Estimate the total addressable market (TAM) for business travel booking solutions in Europe. - 7
Type · Competitive Analysis
Who are Duffel's main competitors in the flight API space, and what are their key strengths and weaknesses compared to us? - + 1 more questions in this round (sign up to unlock)
5
Behavioral / Leadership
3- 8
Type · Conflict Resolution
Describe a moment when you had to reconcile the conflicting requirements of a high-volume travel agency partner needing a specific API response field and the engineering team's mandate to minimize technical debt and maintain schema stability. How did you navigate this technical trade-off? - 9
Type · Prioritization
Describe a situation where you had too many competing priorities and limited resources. How did you decide what to focus on, and what did you do about the items you couldn't address? - + 1 more questions in this round (sign up to unlock)
Unlock all 14 Duffel 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 Duffel
How Duffel's DNA translates across functions. Pick your role.
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Practice Duffel interviews end-to-end
Duffel Mock Interview
Run a live mock interview with our AI interviewer using Duffel-style prompts. Get scored on structure, signal, and answer length - exactly how the real loop grades you.
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STAR Stories for Duffel Behavioral Rounds
Build a Story Bank of your past wins, mapped to the leadership signals Duffel interviewers grade on. Reuse them across every behavioral round.
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Duffel Interview Prep Hub
The frameworks behind every Duffel 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 Duffel 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 Duffel interview questions shows.
Estimate the total addressable market (TAM) for business travel booking solutions in Europe.
A strong answer shows: Structured approach to estimation.; Ability to break down complex problems.; Sound reasoning and justification of assumptions.; Understanding of market dynamics..
Tell me about a time you had to influence a senior stakeholder or a team that didn't report to you to adopt your product vision or strategy. What was your approach?
A strong answer shows: Influence and persuasion skills.; Strategic communication.; Stakeholder management.; Understanding of organizational dynamics..
Frequently asked questions
How long does the Duffel interview process take?
Most candidates spend between 4 and 8 weeks from recruiter screen to offer. The onsite loop itself runs in a single day or is split across two half-days, with debrief and offer typically within 5 business days after.
How should I prepare specifically for Duffel?
Focus on three things: (1) the company DNA shown above - what they actually grade for, (2) the rounds in your loop, especially the round most candidates underestimate, and (3) drilling on the question types in this guide using a structured framework like CIRCLES or STAR.
Does this apply to engineering or design roles at Duffel?
The DNA stays the same - what changes is the round mix. SWE candidates face coding screens instead of Product Sense; designers face portfolio reviews and design exercises. The "what they value" and behavioral signals carry across all functions.
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