Software Engineer, Fullstack

About Us

Mercari is Japan's biggest C2C marketplace founded in 2013 with the mission to “create value in a global marketplace where anyone can buy & sell”.

From being the first tech unicorn from Japan before its IPO in 2018 we have come a long way towards becoming a global player and continuously and diligently work towards our transformation journey with a strong focus on our mission.

Since its inception, Mercari Group has worked to grow its services, investing in both our people and technology. Over time Mercari has expanded from being the top player in the C2C marketplace in Japan to new geographies like the U.S.

We have also successfully launched new businesses such as Merpay, which is a mobile payment service platform with a vision to create a society where anyone can realize their dreams through a new ecosystem centered not only on payment service but also on credit.

Today, Mercari Group is made up of multiple subsidiary businesses including logistics, B2C platform, blockchain, and sports team management.

For our services to be utilized by people worldwide; however, there is still a mountain of work ahead of us. This endeavor naturally requires the capability of the best talent and minds, and that is exactly the reason for us to launch the India Center of Excellence. With your help, we will continue to take on the world stage and strive to grow into a successful global tech company.

Our Culture

To achieve our mission at Mercari, our organization and each of our employees share the same values and perspectives.

Our individual guidelines for action are defined by our four values:

• Go Bold
• All for One
• Be a Pro
• Move Fast

Our organization is also shaped by our four foundations:

• Sustainability
• Diversity & Inclusion
• Trust & Openness
• Well-being for Performance

Regardless of how big Mercari gets, the culture will remain essential to achieving our mission and something we want to preserve throughout our organization.

We invite you to read the “Mercari Culture Doc,” which summarizes the behaviors and mindset shared by Mercari and its employees. We continue to build an environment where all of our members of diverse backgrounds are accepted and recognized, and where they can thrive while holding dear to Mercari’s culture.

Key ResponsibilitiesProfile Overview

We are seeking a seasoned Full Stack Engineer with ** 5 to 8 years of professional experience** to join our engineering team. The ideal candidate is a versatile technical leader who bridges the ** gap between complex backend architectures and high-performance frontend interfaces **. You will be responsible for designing end-to-end features, mentoring junior engineers, and ensuring our systems are scalable, secure, and resilient.

Key Responsibilities

• End-to-End Development: Design, develop, and maintain scalable full-stack web applications using modern frontend and backend technologies.
• Architecture & Design: Architect complex user interfaces with React/Next.js and design robust backend systems and APIs.
• Quality Assurance: Write comprehensive unit, integration, and E2E tests for both frontend and backend components.
• System Ownership: Lead technical planning, conduct code reviews, and ensure adherence to high standards for performance and security.
• Mentorship: Guide junior engineers, fostering their growth through technical leadership and collaborative problem-solving.
• Optimization: Improve application performance on the client side and optimize database queries and server-side logic on the backend.
• Innovation: Integrate AI-powered development tools into the workflow to increase team productivity and code quality.

Requirements

• Experience: 5 to 8 years of professional software development experience across the full stack.
• Frontend Mastery: Expert-level proficiency in ** React** and ** Next.js** framework.
• Backend Proficiency: Strong experience in backend languages (e.g., ** Go, Node.js, Java, or Python **) and building RESTful or GraphQL APIs.
• Databases: Proficiency with SQL (PostgreSQL, MySQL) and/or NoSQL databases, including schema design and query optimization.
• Testing: Experience with testing frameworks such as Jest, React Testing Library, and backend testing suites (e.g., PyTest, Mocha, or Go testing).
• System Design: Proven ability to design distributed systems, microservices, and scalable frontend architectures.
• Education: Bachelor’s degree in Computer Science, Engineering, or a related field.

Preferred & Nice-to-Have Skills

• AI-Powered Tools: Hands-on experience with modern AI coding assistants (e.g., ** Cursor, GitHub Copilot, Gemini **) to optimize development cycles.
• Infrastructure & DevOps: Experience with CI/CD pipelines, Docker, Kubernetes, and cloud platforms like ** GCP, AWS, or Azure **.
• Advanced Networking: Familiarity with ** gRPC, Protocol Buffers **, or Backend-for-Frontend (BFF) patterns.
• Observability: Experience using tools like ** Grafana or Datadog** to monitor system health and troubleshoot production issues.
• Agile Leadership: Experience leading projects in an Agile/Scrum environment and managing cross-functional technical stakeholders.

What We Offer

• Global Impact: Work on high-traffic projects that impact millions of users.
• Growth: Structured professional development and opportunities to move into next roles.
• Flexibility: Hybrid work arrangements and a focus on work-life balance.
• Benefits: Comprehensive health insurance for you and your family, and a modern office environment.
• Tech-Forward Culture: Access to the latest tools, learning resources, and conferences to keep your skills sharp.

Benefits