Affirm

Software Engineer 2

Software EngineerL5Medium to Hard

The Software Engineer 2 (L5) interview at Affirm is designed to assess a candidate's technical proficiency, problem-solving abilities, system design skills, and cultural fit. This role typically requires 3-5 years of relevant experience. The process involves multiple rounds, including technical interviews, a system design interview, and a behavioral/managerial interview.

Rounds

3

Timeline

~7 days

Experience

3 - 5 yrs

Salary Range

US$130000 - US$160000

Total Duration

150 min

Overall Evaluation Criteria

Technical Skills

Problem-solving skills: Ability to break down complex problems, identify edge cases, and devise efficient solutions.
Coding proficiency: Clean, well-structured, and efficient code.
Data structures and algorithms: Understanding and application of fundamental CS concepts.
System design: Ability to design scalable, reliable, and maintainable systems.
Communication: Clarity in explaining technical concepts and thought processes.
Collaboration: Ability to work effectively with others and contribute to team goals.
Cultural fit: Alignment with Affirm's values and work environment.

Behavioral and Cultural Fit

Behavioral competencies: Demonstrating leadership, teamwork, adaptability, and ownership.
Experience relevance: How past experiences align with the requirements of the role.
Motivation and interest: Enthusiasm for Affirm's mission and the specific role.

Preparation Tips

1Review fundamental data structures and algorithms (arrays, linked lists, trees, graphs, hash maps, sorting, searching).
2Practice coding problems on platforms like LeetCode, HackerRank, or similar.
3Study system design principles (scalability, availability, consistency, databases, caching, load balancing, message queues).
4Prepare to discuss your past projects in detail, focusing on your contributions and technical challenges.
5Understand Affirm's business model, products, and values.
6Practice behavioral questions using the STAR method (Situation, Task, Action, Result).
7Prepare questions to ask the interviewer about the role, team, and company culture.

Study Plan

1

Data Structures and Algorithms Fundamentals

Weeks 1-2: Data Structures & Algorithms (Easy/Medium)

Week 1-2: Focus on core data structures (arrays, linked lists, stacks, queues, trees, graphs, hash tables) and algorithms (sorting, searching, recursion, dynamic programming). Practice implementing these and solving related problems on platforms like LeetCode (Easy/Medium).

2

System Design Principles

Week 3: System Design Concepts

Week 3: Deep dive into system design concepts. Study topics like API design, database choices (SQL vs. NoSQL), caching strategies, load balancing, message queues, and distributed system patterns. Read relevant articles and case studies.

3

System Design Application

Week 4: System Design Practice

Week 4: Practice system design problems. Work through common scenarios like designing a URL shortener, a Twitter feed, or a rate limiter. Focus on trade-offs and justifying your design choices.

4

Behavioral Interview Preparation

Week 5: Behavioral Interview Prep

Week 5: Prepare for behavioral interviews. Reflect on your past experiences and prepare stories using the STAR method for common questions related to teamwork, leadership, conflict resolution, and handling failure.

5

Company and Role Alignment

Week 6: Company Research & Questions

Week 6: Review Affirm's business, products, and values. Research recent news and company initiatives. Prepare thoughtful questions to ask the interviewers.

Commonly Asked Questions

Given an array of integers, find the contiguous subarray with the largest sum.
Design a system to shorten URLs.
Describe a time you had to deal with a difficult stakeholder.
How would you implement a cache for a web application?
What are the differences between TCP and UDP?
Tell me about a project you are particularly proud of.
How do you handle production incidents?
Design a notification system.
Explain the concept of eventual consistency.
What are your career goals?

Location-Based Differences

San Francisco, USA

Interview Focus

Emphasis on practical application of data structures and algorithms.Deeper dive into distributed systems concepts relevant to Affirm's platform.Understanding of cloud-native technologies (AWS, Kubernetes).Cultural alignment with Affirm's values (e.g., customer obsession, bias for action).

Common Questions

Discuss a challenging technical problem you solved at your previous company.

How do you approach debugging a complex issue in a distributed system?

Describe a time you had to mentor a junior engineer.

What are your thoughts on microservices vs. monolith architectures in the context of e-commerce?

How do you ensure the scalability and reliability of your code?

Tips

Be prepared to discuss specific examples from your experience that demonstrate problem-solving and collaboration.
Familiarize yourself with Affirm's business and how technology supports it.
Practice explaining complex technical concepts clearly and concisely.
Research common interview questions for L5 Software Engineers at similar tech companies.

Remote (Global)

Interview Focus

Focus on system design and architectural patterns.Understanding of scalability, performance, and reliability in a global context.Experience with data processing and analytics pipelines.Demonstrated ability to work effectively in a remote or hybrid team environment.

Common Questions

Explain the trade-offs between different database technologies for a high-throughput application.

How would you design a rate-limiting system for an API?

Describe a situation where you disagreed with a technical decision and how you handled it.

What are the key considerations for building a fault-tolerant system?

How do you stay updated with new technologies and best practices?

Tips

Prepare to draw system diagrams and explain your design choices thoroughly.
Highlight experience with internationalization and localization if applicable.
Showcase your ability to communicate technical ideas effectively across different teams and time zones.
Understand the challenges of operating at scale in different regulatory environments.

Process Timeline

1
Data Structures and Algorithms45m
2
System Design60m
3
Behavioral and Managerial Fit45m

Interview Rounds

3-step process with detailed breakdown for each round

1

Data Structures and Algorithms

Coding challenge focused on data structures and algorithms.

Technical Interview (Coding)Medium
45 minSoftware Engineer

This round focuses on your fundamental programming skills. You will be asked to solve one or two coding problems, typically involving data structures and algorithms. The interviewer will assess your ability to understand the problem, devise a solution, write clean code, and explain your thought process. Expect to discuss time and space complexity and potential optimizations.

What Interviewers Look For

Strong problem-solving skills.Proficiency in at least one programming language.Ability to write clean and efficient code.Understanding of time and space complexity.

Evaluation Criteria

Correctness of the solution.
Efficiency of the algorithm (time and space complexity).
Code clarity and style.
Ability to explain the thought process.
Handling of edge cases.

Questions Asked

Given a binary tree, invert the tree.

TreeRecursionBinary Tree

Find the kth largest element in an unsorted array.

ArraySortingHeap

Preparation Tips

1Practice coding problems on platforms like LeetCode, focusing on medium-difficulty questions.
2Be comfortable explaining your approach before you start coding.
3Write code that is readable and well-commented.
4Test your code with various inputs, including edge cases.

Common Reasons for Rejection

Inability to solve coding problems efficiently.
Poor code quality (not clean, readable, or maintainable).
Lack of understanding of fundamental data structures and algorithms.
Failure to consider edge cases or optimize solutions.
2

System Design

Design a scalable system based on a given problem statement.

System Design InterviewHard
60 minSenior Software Engineer / Architect

This round assesses your ability to design scalable and robust systems. You'll be given an open-ended problem (e.g., design a URL shortener, a social media feed) and expected to design a high-level architecture. This includes defining APIs, choosing databases, discussing caching strategies, load balancing, and addressing potential bottlenecks and failure scenarios.

What Interviewers Look For

Ability to design complex systems from scratch.Understanding of trade-offs in system design.Knowledge of distributed systems, databases, caching, and messaging.Ability to communicate design ideas effectively.

Evaluation Criteria

Scalability of the proposed design.
Reliability and fault tolerance.
Clarity and completeness of the design.
Justification of technology choices and trade-offs.
Ability to handle various constraints and requirements.
Understanding of distributed systems concepts.

Questions Asked

Design a rate limiter for an API.

System DesignAPIScalability

Design a distributed cache system.

System DesignDistributed SystemsCaching

Preparation Tips

1Study common system design patterns and concepts.
2Practice designing various systems, focusing on trade-offs.
3Be prepared to draw diagrams and explain your design choices.
4Ask clarifying questions to understand the scope and constraints of the problem.

Common Reasons for Rejection

Inability to design a scalable and reliable system.
Lack of understanding of core system design concepts.
Poor justification of design choices and trade-offs.
Failure to consider aspects like availability, consistency, and performance.
Not asking clarifying questions.
3

Behavioral and Managerial Fit

Assesses cultural fit, teamwork, and past experiences.

Behavioral / Managerial InterviewMedium
45 minHiring Manager / Engineering Manager

This round focuses on your behavioral and cultural fit. The interviewer will ask questions about your past experiences, how you handle different situations (e.g., conflict, failure, success), your motivations, and your career goals. Using the STAR method (Situation, Task, Action, Result) is highly recommended for answering these questions.

What Interviewers Look For

Cultural fit with Affirm.Ability to work effectively in a team.Demonstrated ownership and accountability.Growth mindset and willingness to learn.Good communication and interpersonal skills.

Evaluation Criteria

Alignment with Affirm's core values.
Collaboration and teamwork skills.
Problem-solving approach in past experiences.
Leadership potential.
Communication clarity.
Motivation and career aspirations.

Questions Asked

Tell me about a time you failed and what you learned from it.

BehavioralFailureLearning

Describe a situation where you had to work with a difficult team member.

BehavioralTeamworkConflict Resolution

Preparation Tips

1Prepare specific examples using the STAR method for common behavioral questions.
2Research Affirm's company culture and values.
3Be ready to discuss your strengths and weaknesses.
4Show enthusiasm for the role and the company.

Common Reasons for Rejection

Lack of alignment with company values.
Poor communication or interpersonal skills.
Inability to provide specific examples for behavioral questions.
Lack of enthusiasm or interest in the role/company.
Negative attitude or inability to handle feedback.

Commonly Asked DSA Questions

Frequently asked coding questions at Affirm

View all
Group AnagramsMEDIUMValid AnagramEASYCoin ChangeMEDIUMInsert Delete GetRandom O(1)MEDIUMInsert Delete GetRandom O(1) - Duplicates allowedHARDString CompressionMEDIUMParse Lisp ExpressionHARDNumber of Recent CallsEASYShortest Uncommon Substring in an ArrayMEDIUMString Compression IIIMEDIUM