Type · api-design
Design an API for Adfin's core transaction processing service. Consider aspects like idempotency, rate limiting, request/response formats, and error handling for a high-throughput fintech environment.
How to Pass the Adfin Software Engineer Interview in 2026
Growth · Software Engineer Interview Guide
Sign up to see ATSHeadquartered in United KingdomInterview language: English
The Adfin DNA (TL;DR)
Adfin's interview rounds prioritize a candidate's ability to articulate complex financial concepts, particularly how their contributions would enhance Adfin's Analytics platform. Interviewers look for clear, structured thinking and a deep understanding of financial workflows, often probing for metric-with-denominator examples.
The Adfin 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 problems, reasoning about defects, 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 Adfin interview outcomes, avoid these common traps:
- Using data structures that don't scale well with the number of rules or transactions.
- Inefficiently managing memory, leading to unbounded growth with the stream.
- Using a naive approach that re-scans the entire stream for each calculation.
- Not accounting for data schema evolution or data quality checks.
Test Yourself: Real Adfin Questions
Three real prompts pulled from our database.
Type · motivation
Why are you interested in joining Adfin, a fintech company focused on growth and user acquisition, as a Software Engineer?
Type · data-structures
Given a stream of financial transactions, implement a data structure that can efficiently calculate the moving average of the transaction amounts over the last N transactions.
+ many more questions, signals, and worked examples
Sign up to unlock the full Adfin grading rubric
Adfin Interview Question Bank
A sample from our database, grouped by round. Sign up to see the full set.
9 of 12 questions shown
1
Recruiter Screen
1- 1
Type · motivation
Why are you interested in joining Adfin, a fintech company focused on growth and user acquisition, as a Software Engineer?
2
Coding Screen
3- 2
Type · data-structures
Given a stream of financial transactions, implement a data structure that can efficiently calculate the moving average of the transaction amounts over the last N transactions. - 3
Type · algorithms
A/B testing is crucial for growth. You are given two sets of user data, 'control' and 'treatment', each with a list of conversion events. Write a function to determine if the conversion rate difference is statistically significant using a standard hypothesis test (e.g., z-test for proportions). - + 1 more questions in this round (sign up to unlock)
3
System Design
3- 4
Type · api-design
Design an API for Adfin's core transaction processing service. Consider aspects like idempotency, rate limiting, request/response formats, and error handling for a high-throughput fintech environment. - 5
Type · scalability
Adfin's user base is growing rapidly. How would you design a system to handle a 10x increase in concurrent users accessing their financial dashboards, ensuring low latency and high availability? - + 1 more questions in this round (sign up to unlock)
4
Onsite Coding
2- 6
Type · debugging
Root Cause Analysis (Issue Tree + 5 Whys)A critical bug is reported: users are sometimes seeing incorrect balances on their dashboard. The backend logs show intermittent `NaN` values being returned for balance calculations. Debug this issue and propose a fix. Assume the calculation involves multiple microservices. - 7
Type · algorithms
Implement a function to detect fraudulent transactions based on a set of rules. For example, flag transactions exceeding a certain amount, occurring in rapid succession from the same user, or originating from a known suspicious IP address. Optimize for performance as transaction volume is high.
5
Behavioral / Leadership
3- 8
Type · conflict-resolution
STAROur engineering team recently debated whether to prioritize low-latency transaction processing or high-fidelity audit logging for our analytics platform. Describe a situation where you advocated for a specific technical trade-off in a high-stakes financial environment, how you handled the pushback from stakeholders concerned about regulatory compliance, and the eventual impact on system performance. - 9
Type · ownership
STARAt Adfin, we often identify discrepancies in real-time reporting that require cross-service investigation. Tell us about a time you identified a subtle data drift or latency bottleneck in a distributed financial pipeline that was impacting our analytics dashboard. How did you investigate the root cause across service boundaries and ensure the fix prevented future regression? - + 1 more questions in this round (sign up to unlock)
Unlock all 12 Adfin 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 Adfin
How Adfin's DNA translates across functions. Pick your role.
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Practice Adfin interviews end-to-end
Adfin Mock Interview
Run a live mock interview with our AI interviewer using Adfin-style prompts. Get scored on structure, signal, and answer length - exactly how the real loop grades you.
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STAR Stories for Adfin Behavioral Rounds
Build a Story Bank of your past wins, mapped to the leadership signals Adfin interviewers grade on. Reuse them across every behavioral round.
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Adfin Interview Prep Hub
The frameworks behind every Adfin 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 Adfin 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 Adfin interview questions shows.
Design an API for Adfin's core transaction processing service. Consider aspects like idempotency, rate limiting, request/response formats, and error handling for a high-throughput fintech environment.
A strong answer shows: API design principles; Scalability; Reliability; Fintech considerations.
Why are you interested in joining Adfin, a fintech company focused on growth and user acquisition, as a Software Engineer?
A strong answer shows: Interest in fintech; Understanding of Adfin's business; Alignment with company values.
Frequently asked questions
How long does the Adfin 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 Adfin?
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 Adfin?
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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