# Software Engineer
**Role:** Software Engineer · **Level:** MG2
**Company:** [Mercari](https://scaleengineer.com/companies/mercari)
**Difficulty:** Medium to Hard
**Salary:** US$110000 - US$150000
**Experience:** 5 - 8
**Timeline:** ~14 days
Mercari is looking for a talented Software Engineer at the MG2 level to join our dynamic team. This role involves designing, developing, and maintaining scalable and high-quality software solutions that power our e-commerce platform. You will collaborate with cross-functional teams to deliver innovative features and contribute to the continuous improvement of our engineering practices.
Canonical: https://scaleengineer.com/interviews/mercari/mg2-software-engineer
---
## Overall evaluation

- Technical Skills & Problem Solving
- System Design & Architecture
- Behavioral & Cultural Fit

## Questions asked

- Describe a complex system you designed or contributed to. What were the key challenges and how did you overcome them?
- How would you design a URL shortening service like bit.ly?
- Given a large dataset, how would you find the top K most frequent elements?
- Tell me about a time you disagreed with a technical decision made by your team. How did you handle it?
- How do you ensure the scalability and reliability of your code?
- What are the trade-offs between different database technologies (e.g., SQL vs. NoSQL)?
- Explain the concept of eventual consistency.
- How would you optimize the performance of a web application?
- Describe your experience with CI/CD pipelines.
- What are your thoughts on microservices vs. monolithic architectures?

## Preparation tips

### lists

- Review core computer science concepts, including data structures, algorithms, and complexity analysis.
- Practice coding problems on platforms like LeetCode, HackerRank, or similar.
- Study system design principles and common architectural patterns.
- Prepare to discuss your past projects in detail, focusing on your contributions and technical challenges.
- Research Mercari's products, services, and engineering culture.
- Prepare questions to ask the interviewers about the role, team, and company.
- Practice behavioral questions using the STAR method (Situation, Task, Action, Result).

### studyPlan

- {"title":"Data Structures & Algorithms","longDescription":"Weeks 1-2: Focus on Data Structures and Algorithms. Cover arrays, linked lists, trees, graphs, hash tables, sorting, searching, dynamic programming, and greedy algorithms. Practice problems related to each topic, aiming for optimal solutions.","shortDescription":"Weeks 1-2: DSA fundamentals and practice."}
- {"title":"System Design","longDescription":"Weeks 3-4: Dive into System Design. Study concepts like scalability, availability, reliability, load balancing, caching, databases (SQL vs. NoSQL), message queues, and API design. Work through common system design interview questions.","shortDescription":"Weeks 3-4: System Design principles and patterns."}
- {"title":"Behavioral & Situational","longDescription":"Week 5: Prepare for Behavioral and Situational questions. Reflect on your past experiences and prepare examples using the STAR method. Understand Mercari's values and how your experiences align with them.","shortDescription":"Week 5: Behavioral questions and STAR method."}
- {"title":"Project Review & Tech Stack","longDescription":"Week 6: Review your projects and prepare to discuss them in detail. Brush up on specific technologies relevant to Mercari's stack (e.g., Go, Java, Python, AWS, Kubernetes). Practice mock interviews.","shortDescription":"Week 6: Project deep dive and tech stack review."}

## Location differences

- {"location":"Remote/Hybrid","differences":{"tips":["Be prepared to discuss specific examples of scaling challenges you've faced.","Familiarize yourself with Mercari's tech stack and common architectural patterns.","Highlight any experience with performance tuning and optimization.","Showcase your ability to work effectively in a remote or hybrid team setting."],"interviewFocus":["Deep understanding of distributed systems and scalability.","Experience with cloud platforms (AWS, GCP, Azure).","Proficiency in backend development languages (e.g., Go, Java, Python).","Strong problem-solving skills in a high-traffic environment."],"commonQuestions":["How would you handle a sudden surge in traffic on our platform?","Describe a time you had to optimize a slow-performing database query.","What are your strategies for ensuring code quality and maintainability in a large codebase?","Discuss your experience with cloud-native architectures (e.g., microservices, serverless)."]}}
- {"location":"On-site (Tokyo)","differences":{"tips":["Prepare to walk through your design process for a complex system.","Be ready to articulate your reasoning behind technical decisions.","Emphasize your ability to mentor junior engineers.","Showcase your understanding of Mercari's business domain and user needs."],"interviewFocus":["System design and architectural thinking.","Problem-solving and analytical skills.","Collaboration and communication within a team.","Understanding of software development lifecycle and best practices."],"commonQuestions":["How do you approach designing a new feature from scratch?","Describe a challenging technical problem you solved and your thought process.","What are your thoughts on testing strategies for microservices?","How do you stay updated with the latest industry trends and technologies?"]}}

## Round 1: Technical Coding Round 1
**Type:** Data Structures and Algorithms Interview · **Difficulty:** Medium · **Duration:** 45 min
Coding challenge focused on DSA.
This round focuses on your fundamental programming skills. You will be asked to solve one or two coding problems that test your knowledge of data structures and algorithms. The interviewer will assess your ability to write clean, efficient, and correct code, as well as your approach to problem-solving and your communication skills.
**Interviewers look for:** Strong grasp of DSA.; Clean and efficient coding practices.; Problem-solving approach.; Ability to communicate technical ideas.
**Evaluation criteria:** Correctness of the solution.; Efficiency of the algorithm (time and space complexity).; Code clarity and readability.; Ability to explain the thought process.; Handling of edge cases.
**Common rejection reasons:** Inability to articulate thought process clearly.; Lack of understanding of fundamental data structures and algorithms.; Inefficient or incorrect code implementation.; Poor time management during the coding exercise.
## Questions

- Given an array of integers, find the contiguous subarray with the largest sum.
- Implement a function to reverse a linked list.
- Find the kth smallest element in a binary search tree.

## Preparation tips

- Practice coding problems regularly.
- Understand the time and space complexity of your solutions.
- Be prepared to explain your approach before you start coding.
- Test your code with various inputs, including edge cases.

## Round 2: System Design Round
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Design a scalable system.
In this round, you will be presented with a high-level system design problem. You'll need to design a scalable and reliable system, discussing various components, their interactions, and potential bottlenecks. The focus is on your ability to think critically about system architecture, trade-offs, and how to build for scale.
**Interviewers look for:** Strong system design thinking.; Knowledge of distributed systems.; Ability to handle ambiguity.; Pragmatic approach to problem-solving.
**Evaluation criteria:** Clarity and completeness of the system design.; Scalability and performance considerations.; Reliability and fault tolerance.; Understanding of trade-offs between different design choices.; Ability to justify design decisions.
**Common rejection reasons:** Inability to design a scalable and robust system.; Lack of consideration for trade-offs and constraints.; Poor understanding of distributed systems concepts.; Failure to address potential failure points.
## Questions

- Design a system to handle real-time analytics for a website.
- Design a distributed key-value store.
- Design a notification service.

## Preparation tips

- Study common system design patterns.
- Practice designing large-scale systems like Twitter feed, URL shortener, etc.
- Think about scalability, availability, consistency, and latency.
- Be prepared to discuss database choices, caching strategies, and load balancing.

## Round 3: Behavioral & Cultural Fit Round
**Type:** Behavioral Interview · **Difficulty:** Medium · **Duration:** 45 min
Assess behavioral and cultural fit.
This round assesses your behavioral and situational competencies. You'll be asked questions about your past experiences, how you handle challenges, work in teams, and your motivations. The goal is to understand your working style, your ability to collaborate, and how you align with Mercari's culture and values.
**Interviewers look for:** Collaboration and teamwork.; Ownership and accountability.; Adaptability and resilience.; Alignment with Mercari's culture.
**Evaluation criteria:** Teamwork and collaboration skills.; Communication effectiveness.; Problem-solving approach in past projects.; Adaptability and learning agility.; Cultural fit with Mercari's values.
**Common rejection reasons:** Poor communication or interpersonal skills.; Lack of alignment with company values.; Inability to provide specific examples of past experiences.; Negative attitude or lack of enthusiasm.
## Questions

- Tell me about a time you faced a significant technical challenge. How did you approach it, and what was the outcome?
- Describe a situation where you had to work with a difficult team member. How did you manage the relationship?
- Why are you interested in Mercari and this specific role?

## Preparation tips

- Prepare examples using the STAR method.
- Be honest and authentic in your responses.
- Show enthusiasm for the role and the company.
- Ask thoughtful questions about the team and culture.