Software Engineer, Backend - US App

Software Engineer, Backend - US App

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

For more details, see the Overview of Our Positions.

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About the Role

The mission is to circulate all forms of value to unleash the potential in all people. The vision is to connect people globally and empower anyone to realize their dreams through technology.

Learn more about the culture and mission:

• Culture Doc

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Engineering Principles

Fundamental engineering beliefs and behavior are built around:

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

Read more about Engineering Culture.

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Responsibilities

• Lead development of complex backend features and services (e.g., payment processing, inventory management)
• Design and implement scalable backend architectures (microservices, event-driven systems)
• Drive technical decisions and best practices: coding standards, performance, testing strategies
• Mentor engineers through code reviews and technical presentations
• Collaborate with product and frontend teams to define requirements and feature feasibility
• Optimize backend for performance and scalability (databases, caching, load balancing)
• Contribute to backend platform roadmap, including technology evaluation and reducing technical debt
• Lead technical discussions and architectural reviews

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Unique Challenges

• Work in a small distributed team, responsible for the entire US backend serving millions of daily active users
• Collaborate globally with teammates in Tokyo and the US
• Represent the US in group-wide shared platform components

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Qualifications

Required:

• Deep understanding of backend performance optimization
• Strong architectural and system design skills
• Excellent mentoring and technical leadership

Preferred:

• Expert knowledge of Go and PHP
• MySQL, Spanner, Google Cloud Platform, Kubernetes
• Excellent knowledge of Agentic AI tools/workflows

Languages:

• English: Business level (CEFR B2 or higher) required
• Japanese: Basic (CEFR A2) optional
  About CEFR

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Learn More

• Careers site
• Mercan
• Social media: X / LinkedIn

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Recruiting Process

• Application screening
• Skill assessment (HackerRank or GitHub, for engineering)
• Interviews (number varies)
• Reference check (timing: around final interview)
• Offer (made after final interview and reference check)

More details: Recruitment Process

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Equal Opportunity

Committed to Inclusion & Diversity, eliminating discrimination to provide equal opportunity for all, regardless of background.
Read the I&D Statement.

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