# Software Engineer
**Role:** Software Engineer · **Level:** MG1
**Company:** [Mercari](https://scaleengineer.com/companies/mercari)
**Difficulty:** Medium to Hard
**Salary:** US$110000 - US$150000
**Experience:** 3 - 7
**Timeline:** ~14 days
Mercari's Software Engineer (MG1) interview process is designed to assess a candidate's technical proficiency, problem-solving abilities, and cultural fit within the company. The process typically involves multiple rounds, starting with an initial screening and progressing through technical interviews, a system design round, and a final managerial or behavioral interview. The goal is to identify candidates who can contribute effectively to Mercari's innovative and collaborative environment.
Canonical: https://scaleengineer.com/interviews/mercari/mg1-software-engineer
---
## Overall evaluation

- Technical Skills
- System Design
- Behavioral and Cultural Fit

## Questions asked

- Given an array of integers, find the contiguous subarray with the largest sum.
- Design a system like Instagram's news feed.
- How would you implement a rate limiter?
- Tell me about a time you failed and what you learned from it.
- Explain the difference between TCP and UDP.
- How do you handle concurrency in your applications?
- Describe the process of deploying a new feature in a production environment.
- What are the trade-offs when choosing between different database technologies?
- How do you approach debugging a complex issue in a distributed system?
- Tell me about a project you are particularly proud of.

## Preparation tips

### lists

- Review fundamental data structures (arrays, linked lists, trees, graphs, hash maps) and algorithms (sorting, searching, dynamic programming, graph traversal).
- Practice coding problems on platforms like LeetCode, HackerRank, or AlgoExpert, focusing on medium to hard difficulty.
- Study system design concepts, including scalability, availability, consistency, databases, caching, load balancing, and microservices.
- Prepare to discuss your past projects in detail, highlighting your contributions and the technical challenges you overcame.
- Understand Mercari's business model, products, and company culture. Research their engineering blog and recent news.
- Practice behavioral questions using the STAR method (Situation, Task, Action, Result) to structure your answers.
- Be ready to explain your thought process clearly and articulate your solutions effectively.

### studyPlan

- {"title":"Data Structures and Algorithms Fundamentals","longDescription":"Weeks 1-2: Focus on core data structures (arrays, linked lists, stacks, queues, trees, graphs, hash tables) and their common operations. Practice basic algorithms like sorting (quicksort, mergesort) and searching (binary search). Solve 10-15 easy and medium LeetCode problems per week.","shortDescription":"Weeks 1-2: Data Structures & Basic Algorithms. Solve 20-30 easy/medium LeetCode problems."}
- {"title":"Advanced Algorithms","longDescription":"Weeks 3-4: Dive deeper into algorithms, including dynamic programming, greedy algorithms, graph algorithms (BFS, DFS, Dijkstra's), and string manipulation. Continue practicing medium and start tackling some hard LeetCode problems. Aim for 15-20 problems per week.","shortDescription":"Weeks 3-4: Advanced Algorithms. Solve 30-40 medium/hard LeetCode problems."}
- {"title":"System Design Fundamentals","longDescription":"Weeks 5-6: Begin system design preparation. Study concepts like load balancing, caching strategies, database choices (SQL vs. NoSQL), message queues, and microservices architecture. Read system design primers and watch relevant videos. Practice designing common systems like Twitter feed or URL shortener.","shortDescription":"Weeks 5-6: System Design Basics. Study load balancing, caching, databases, microservices. Practice designing simple systems."}
- {"title":"Behavioral and Advanced System Design","longDescription":"Weeks 7-8: Focus on behavioral preparation. Reflect on your past experiences and prepare stories using the STAR method for common behavioral questions (teamwork, conflict resolution, leadership, failure). Research Mercari's values and prepare to articulate how you align with them. Continue practicing system design for more complex scenarios.","shortDescription":"Weeks 7-8: Behavioral Prep & Advanced System Design. Practice STAR method. Research Mercari values. Design complex systems."}

## Location differences

- {"location":"Tokyo, Japan","differences":{"tips":["Be prepared to discuss specific examples from your past projects that demonstrate your skills.","Research Mercari's tech stack and recent product launches.","Practice explaining complex technical concepts clearly and concisely.","Understand Mercari's company values and how they align with your own."],"interviewFocus":["Emphasis on practical application of data structures and algorithms relevant to e-commerce.","Strong focus on system design principles and scalability for high-traffic applications.","Behavioral questions often probe collaboration and problem-solving in a team context.","Understanding of cloud technologies (AWS, GCP) and their application in e-commerce."],"commonQuestions":["How would you design a system to handle real-time notifications for Mercari's app?","Describe a challenging technical problem you faced and how you solved it.","What are your thoughts on microservices architecture for an e-commerce platform?","How do you ensure code quality and maintainability in a large project?","Tell me about a time you had to disagree with a team member or manager. How did you handle it?"]}}
- {"location":"Remote (Global)","differences":{"tips":["Prepare to whiteboard your solutions for coding and system design problems.","Be ready to discuss your thought process and justify your design choices.","Highlight any experience with international teams or projects.","Showcase your ability to learn quickly and contribute to a fast-paced environment."],"interviewFocus":["Focus on data structures and algorithms, with a slight lean towards practical coding challenges.","System design questions often involve scaling and performance optimization for global user bases.","Behavioral questions assess adaptability, learning agility, and proactive problem-solving.","Familiarity with distributed systems and cloud-native architectures is highly valued."],"commonQuestions":["Design an API for a feature like 'saved items' on Mercari.","How would you optimize database queries for a large-scale e-commerce platform?","Discuss your experience with A/B testing and its impact on product development.","What are the trade-offs between monolithic and microservices architectures?","Describe a situation where you had to adapt to a significant change in project requirements."]}}

## Round 1: Coding Round 1
**Type:** Technical Interview (Coding) · **Difficulty:** Medium · **Duration:** 45 min
Solve 1-2 coding problems focusing on data structures and algorithms.
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 communication.
**Interviewers look for:** Clean, well-organized code.; Logical and systematic approach to problem-solving.; Understanding of time and space complexity.; Ability to test their code.; Clear communication of their thought process.
**Evaluation criteria:** Correctness of the solution; Efficiency of the solution (time and space complexity); Code readability and maintainability; Problem-solving approach; Ability to communicate the solution
**Common rejection reasons:** Inability to articulate thought process.; Poorly structured or inefficient code.; Fundamental misunderstanding of data structures or algorithms.; Not asking clarifying questions.
## Questions

- Given a binary tree, invert the tree.
- Find the kth largest element in an unsorted array.

## Preparation tips

- Practice coding problems on platforms like LeetCode.
- Focus on understanding the underlying data structures and algorithms.
- Write pseudocode before coding.
- Test your code thoroughly with edge cases.
- Explain your thought process as you code.

## Round 2: System Design Round
**Type:** System Design Interview · **Difficulty:** Hard · **Duration:** 60 min
Design a scalable system based on a given prompt.
This round assesses your ability to design complex, scalable, and reliable systems. You will be given an open-ended problem (e.g., design a URL shortener, a social media feed, or a ride-sharing service) and expected to discuss various aspects of the design, including data modeling, API design, scalability, and performance.
**Interviewers look for:** A structured approach to system design.; Knowledge of distributed systems concepts.; Ability to justify design choices.; Consideration of edge cases and failure modes.; Clear communication of complex ideas.
**Evaluation criteria:** Scalability of the proposed solution; Availability and reliability considerations; Choice of appropriate technologies and data stores; Understanding of trade-offs; Ability to handle constraints and requirements
**Common rejection reasons:** Inability to design a scalable and robust system.; Lack of understanding of trade-offs in design decisions.; Over-simplification or over-complication of the design.; Poor handling of edge cases and failure scenarios.
## Questions

- Design a system like Twitter's trending topics.
- Design an API for a ride-sharing service.

## Preparation tips

- Study common system design patterns and concepts.
- Practice designing various systems.
- Be prepared to discuss trade-offs between different approaches.
- Think about scalability, availability, and reliability.
- Clearly articulate your design choices and reasoning.

## Round 3: Behavioral and Managerial Round
**Type:** Behavioral / Managerial Interview · **Difficulty:** Medium · **Duration:** 45 min
Discuss past experiences, teamwork, and cultural fit.
This round focuses on your behavioral and cultural fit. The interviewer will ask questions about your past experiences, how you handle different situations, your strengths and weaknesses, and your career goals. The aim is to understand how you collaborate, solve problems in a team setting, and whether you align with Mercari's values.
**Interviewers look for:** Enthusiasm and passion for technology.; Ability to work effectively in a team.; Proactive attitude towards problem-solving.; Honesty and self-awareness.; Alignment with Mercari's mission and values.
**Evaluation criteria:** Cultural fit with Mercari's values; Teamwork and collaboration abilities; Problem-solving approach in real-world scenarios; Communication and interpersonal skills; Motivation and career aspirations
**Common rejection reasons:** 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.
## Questions

- Tell me about a time you had to deal with a difficult stakeholder.
- Describe a situation where you had to go above and beyond your regular duties.
- What are your strengths and weaknesses?

## Preparation tips

- Prepare examples using the STAR method.
- Research Mercari's company values and culture.
- Be ready to discuss your career aspirations.
- Ask thoughtful questions about the team and the role.
- Be genuine and enthusiastic.

## Round 4: Team-Specific Technical Round
**Type:** Technical Deep Dive / Team Fit · **Difficulty:** Medium · **Duration:** 45 min
Discuss specific technical skills and team-specific challenges.
This is often a final technical round, sometimes referred to as a 'deep dive' or 'team fit' interview. It might involve more specific technical questions related to the team's domain, or a discussion about a past project in greater detail. The goal is to ensure you have the necessary skills and can integrate well with the specific team you'd be joining.
**Interviewers look for:** Deep understanding of specific technologies relevant to the team.; Ability to engage in technical discussions.; Willingness to learn and grow.; Collaborative spirit.; Potential to contribute to the team's goals.
**Evaluation criteria:** Depth of technical knowledge; Ability to learn and adapt; Problem-solving approach; Communication clarity; Fit with the specific team's needs
**Common rejection reasons:** Significant gaps in technical knowledge.; Inability to adapt to feedback.; Poor communication during the interview.; Lack of alignment with the team's technical direction.
## Questions

- How would you optimize a slow database query in a production environment?
- Describe your experience with containerization technologies like Docker.
- Walk me through a challenging bug you encountered and how you debugged it.

## Preparation tips

- Understand the specific technologies and challenges of the team you are interviewing for.
- Be prepared to discuss your experience with relevant tools and frameworks.
- Think about how your skills can benefit the team.
- Ask questions about the team's current projects and challenges.