Senior Software Engineer

本ポジションは日本語JDの用意がありません。

Senior Software engineer, Android (Mobile Enablement) - Mercari

• Employment Status:　Full-time 
• Work Hours: Full Flextime (no core time)  
• Office: Roppongi

For more details, see the Overview of Our Positions section on our Careers site.

About Mercari

Circulate all forms of value to unleash the potential in all people

"What can I do to help society thrive with the finite resources we have?" The Mercari marketplace app was born in 2013 out of this thought by our founder Shintaro Yamada as he traveled the world. We believe that by circulating all forms of value, not just physical things and money, we can create opportunities for anyone to realize their dreams and contribute to society and the people around them. Mercari aims to use technology to connect people all over the world and create a world where anyone can unleash their potential. For more information about Mercari Group’s mission, see Mercari’s Culture Doc

Organization/Team Mission

Mercari Engineering Principles  

Mercari Engineering Principles are a shared understanding that serves as the foundation of engineering beliefs and behavior at Mercari. The Engineering Principles are designed to complement the organizational identity (Mercari’s mission, values, and culture) from an engineering viewpoint. 

These principles ultimately help us achieve Mercari’s mission by defining the ideal state we seek to realize in the long term. 

• Passion For The Product
• Grow Together
• Solve Through Mechanisms
• Collaborate Openly

For more details, please see the following link:

• Engineering Culture

The Mobile Enablement team transforms mobile development into a seamless, automated, and cross-platform ecosystem. Our mission is to deliver innovative features and user experiences to maximize product-facing impact for Mercari's business. We simplify engineering workflows, reduce repetitive tasks through automation/AI, and enable broader collaboration across teams.

By streamlining coding, testing, releases, and operations, we accelerate innovation and scalability, ensuring mobile development keeps pace with Mercari's global growth and business needs. Join us to redefine how we build and deliver the Mercari experience!

As a Mobile Enabler mainly focusing on the Android ecosystem, you will own and evolve the entire Android engineering ecosystem at Mercari, from lower-level platform capabilities to higher-level architectural decision-making, providing the best experience for our engineers and Mercari users.

Tech Stack

• Android Development: Kotlin, Jetpack Compose, Kotlin Coroutines & Flow
• Build & Tooling: Gradle (Develocity), Android Studio
• API & Data: Protocol Buffers
• AI Tools: Claude Code, Codex, Cursor
• CI/CD: GitHub Actions, GKE

See here for more information about our mission and values.

Work Responsibilities

Specific work responsibilities are listed below:

• Periodically join your fellow product engineers in designing, implementing, and maintain high-quality Android features to understand their reality and define the best solutions for them.
• Own end-to-end development for platform and architectural solutions, from requirements definition through architecture, implementation, testing, and release.
• Lead architectural design for complex features and system components, ensuring maintainability, scalability, and reliability.
• Optimize app performance, startup time, memory usage, and stability across diverse devices and OS versions.
• Work closely with machine learning, backend, infrastructure, product, and design teams to deliver seamless mobile experiences, as well as other feature-owner Android engineering teams.
• Take ownership and evolve Mercari's mobile platform, SDKs, and shared modules used across teams.
• Drive high code quality through code reviews, automated testing, CI/CD improvements, and rigorous documentation.
• Champion engineering best practices and contribute to guidelines and standards across Client Engineering.
• Stay current with the latest developments in Android, Kotlin, Android Views, Jetpack Compose, coroutines, and mobile architecture patterns.
• Bring innovative ideas to improve user experience, developer experience, and operational efficiency.
• Take ownership of initiatives that span multiple teams, driving alignment and technical decision-making.
• Mentor junior and mid-level engineers, helping strengthen the overall technical capabilities of the team and the engineering organization.
  
  

Unique Challenges

• Enabling dozens of mobile engineers in delivering awesome experiences to our 20M+ users by leveraging a diverse skillset to provide the best mobile ecosystem.
• Deliver highly performant and reliable functionality in a fast-paced environment with complex product requirements.
• Bridge consumer-grade UX expectations with robust engineering architecture and infrastructure.
• Influence platform-wide technical strategy, shaping the future direction of Mercari's mobile and AI-native cross-platform ecosystem.
• Lead cross-functional efforts in ambiguous problem spaces where user needs and technical constraints must be balanced.
  
  

Qualifications

• Required Experience/Skills
• Shared belief in the mission and values of the Mercari Group.
• Bachelor's degree in Computer Science, Engineering, or equivalent practical experience.
• Strong proficiency in Kotlin and Android development frameworks (Jetpack libraries, Jetpack Compose, Android SDK).
• Solid understanding of mobile architecture patterns (MVC, MVVM, MVI, Clean Architecture, etc.).
• Demonstrated experience with large-scale mobile applications and complex codebases.
• Experience integrating with backend APIs and asynchronous/concurrent programming.
• Strong analytical and problem-solving skills; ability to navigate ambiguity.
• Excellent communication skills and ability to explain technical concepts clearly.
• Passion for building user-facing mobile products.
• Preferred Experience/Skills
• Experience with large-scale mobile apps serving millions of users.
• Expertise in performance optimization, instrumentation, and mobile observability (e.g., crash analysis, metrics).
• Experience with modern Android platform capabilities (e.g., Kotlin Multiplatform, Baseline Profiles, app performance tooling).
• Contributions to open-source Android projects or active involvement in the mobile community.
• Experience driving technical initiatives across multiple teams or owning platform-level components.
• Familiarity with CI/CD for mobile, automated testing frameworks, build systems (Gradle), and release management.
• UI/UX sensitivity and an eye for detail in crafting polished user experiences.
• Language 
• Japanese: Independent (CEFR - B2) Optional
• English: Independent (CEFR - B2) Required

For details about CEFR, see here.

Learn More About Mercari Group

• Careers site: https://careers.mercari.com/en/   
• Mercan: https://mercan.mercari.com/en/  
• Social media: X / Linkedin 
• Introduction of CoreSRE
• How to deal with legacy systems
• An example of DDL application to a special MySQL configuration
  
  

Recruiting at Mercari

At Mercari Group, we value empathizing with and embodying the mission and values ​​of the Group and each company. To promote the creation of an organization that maximizes the total amount of value exhibited by all members, we would like to understand the experience and skills of each candidate as accurately as possible.

Recruiting cycle at Mercari Group

• Application screening
• Skill assessment: For engineering positions, you will be asked to complete a skill assessment on HackerRank or GitHub. For non-engineering positions, you may be asked to complete an assessment depending on the position. (The timing of the assessment may coincide with the interview process.)
• Interview: The number of interviews may vary depending on the position.
• Reference check: We will ask for online references around the timing of the final interview.
• Offer: Offers will be determined carefully in consideration of the final interview and the reference check.

　Learn more about our recruiting process here.

Equal Opportunity Hiring

Here at Mercari, we work to realize a world in which no one’s potential is limited by their background and everyone has the opportunity to freely create value. We also firmly believe that a mindset of Inclusion & Diversity is essential for us to achieve our mission.

This, of course, extends to our hiring practices as well. Mercari is committed to eliminating discrimination based on age, gender, sexual orientation, race, religion, physical disability, and other such factors so that anyone who shares our mission and values can join us, regardless of their background. For more details, please read our I&D statement.

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