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.

Other roles at Duffel:Product Manager Software Engineer Sales Customer Success Solutions Architect

Growth · Product Manager Interview Guide

Applies via Ashby

How to Pass the Duffel Product Manager Interview in 2026

The Duffel DNA (TL;DR)

Duffel values candidates who demonstrate strong analytical problem-solving, technical proficiency, and a deep understanding of API-first products. They seek individuals who are proactive, customer-centric (especially for developer users), and thrive in a fast-paced, evolving travel tech landscape.

The Duffel Interview Loop

Your onsite loop will typically consist of 5 rounds.

1
Round 1
Recruiter Screen
Motivation, basic fit, logistics.
2
Round 2
Product Sense / Design
Customer empathy, creativity, structured design thinking.
3
Round 3
Analytical / Execution
Metrics definition, root-cause debugging, A/B testing.
4
Round 4
Strategy / Estimation
Market sizing, competitive positioning, business trade-offs.
5
Round 5
Behavioral / Leadership
Past 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:

Describing a situation where they were simply doing their job.
Not considering practical significance alongside statistical significance.
Failing to prioritize investigation steps.
Failing to propose concrete next steps based on the ambiguous result.

Test Yourself: Real Duffel Questions

Three real prompts pulled from our database.

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?

Type · A/B Testing

We're considering a redesign of the flight search results page to make it more visually appealing. How would you design an A/B test to evaluate whether this redesign improves user engagement?

Type · Influence

Describe a situation where you had to persuade a skeptical colleague or stakeholder to adopt your point of view or approach. How did you do it?

+ many more questions, signals, and worked examples

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Duffel Interview Question Bank

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

9 of 22 questions shown

Recruiter Screen

1
Type · Motivation
Why are you interested in Duffel, and what specifically about our mission and the travel industry excites you?

Product Sense / Design

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)

Analytical / Execution

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)

Strategy / Estimation

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)

Behavioral / Leadership

8
Type · Conflict Resolution
Tell me about a time you had a significant disagreement with a cross-functional team member (e.g., engineer, designer, marketer) about a product decision. How did you approach it, and what was the outcome?
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?
+ 9 more questions in this round (sign up to unlock)