Payment Engineer

This software engineering role focuses on payment and financial systems where reliability, security, and transaction accuracy are critical. The engineer works with product managers and business teams from the early project stage to identify underlying problems, propose solutions, and select technologies.

Responsibilities include designing and implementing transaction consistency, error handling, and incident recovery for payment systems. The engineer supports the technical evaluation, selection, and negotiation of acquirers and processors, contributing to cost optimization and risk management. The role also covers systems designed and operated in compliance with the Funds Settlement Act, Installment Sales Act, PCI DSS, and related security standards.

The engineer will help evolve the existing STORES Business Atobarai invoice card payment service and participate in zero-to-one development of new financial services. Cloud infrastructure improvements and observability work are also part of operating services trusted by businesses running physical stores. The position involves balancing AI-centered development speed with the quality required for mission-critical financial systems.

Required experience includes at least five years of web application development and operations, leadership across multiple technical areas from infrastructure through applications, leadership across planning, design, and operations, and a record of delivering difficult projects. Candidates must be able to communicate accurately with internal and external stakeholders, involve the organization in project execution, define goals amid changing conditions, and lead teams or projects to successful outcomes. Fintech development and operations experience, along with deep understanding of payment processes, acquirers, processors, and related business structures, is required.

Preferred experience includes using AI in software development, developing applications with AI multi-agent systems, harness engineering, building AI-agent-based software development environments, driving major system or business transformation, understanding relevant financial regulations and security standards, business process reform, and translating requirements from legal or compliance teams into systems.

The development environment includes Ruby, Ruby on Rails, Java, Spring Boot, Go, AWS, Google Cloud, Cloudflare, RDBMS, MongoDB, Terraform, React, Vue, Next.js, Nuxt, React Router, Swift, SwiftUI, Kotlin, Jetpack Compose, Xcode Cloud, Bitrise, Claude Code, and an in-house AI agent based on the Claude Agent SDK. Google Workspace, Slack, Notion, Claude, Gemini, ChatGPT, Cursor, and GitHub Copilot are also used.

The position is full-time and based in Shibuya, Tokyo. Remote work is available, with at least two office days per month as a general rule. The work schedule is flextime with core hours from 12:00 to 16:00 and eight standard working hours. The probationary period is three months under the same conditions. Annual salary is JPY 8.5–15.5 million. Benefits and leave include health insurance, commuting costs up to JPY 150,000 per month, purchase and training support, paid leave, year-end and New Year holidays, and several family and special leave programs.