Product Engineer (Backend) - Mercari Marketplace New Business Engineering

JD in Japanese follows. 英文の後に和文JDをご覧いただけます。 Product Engineer (Backend) - Mercari Marketplace New Business Engineering Employment Type: Full-timeWork Hours: Flextime system (no core hours)Office: Roppongi For details, see the Overview of Our Positions section of our Careers site. About Mercari Group 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 globe and create a world where anyone can unleash their potential. You can learn more about our mission on the Culture page of our Careers site. Organization/Team Mission Mercari Engineering Principles The Mercari Engineering Principles articulate the shared beliefs and behavioral foundations of Mercari's engineering organization. They are designed to complement—from an engineering perspective—the mission, values, and culture shared by all Mercari members. These principles ultimately help us achieve Mercari's mission by defining the ideal state that we seek to realize in the long term. Passion For The ProductGrow TogetherSolve Through MechanismsCollaborate Openly For more details, see the Culture page of our Mercari Engineering Portal. This team builds emerging marketplace domains that will become Mercari's next growth pillars, including cross-border and new commerce experiences. You will collaborate across Mercari and/or with external partners to turn early hypotheses into scalable products—leveraging the strengths of our existing marketplace while laying the foundation for the next stage of global growth and enabling a safe, global marketplace where sellers and buyers worldwide can transact with confidence. Under a development structure built around AI, we aim to maximize both the value we deliver to users and the speed at which we deliver it. As a Product Engineer at Mercari, you will take end-to-end ownership from spec definition through delivery. We are looking for someone willing to go beyond their role to solve problems, rather than staying confined to their own area of expertise. You will be expected to proactively get involved from the definition phase, and to independently lead every step of the development process—shaping product specs, building consensus, establishing quality and measurement, releasing, and the operations that follow. To learn more about Mercari's mission and values, see the Culture page of our Careers site. Work Responsibilities As a Product Engineer, you will take end-to-end ownership of spec definition through production release in [FILL IN: your team's domain]. Working closely with product managers and other stakeholders, you will finalize specs based on working prototypes and autonomously lead every step, including quality, measurement, release, and the operations that follow. Under a development structure built around AI, you will be responsible for delivering results in a way that balances both speed and quality, from start to finish. Main Responsibilities Leading spec definition and implementation Start from a working prototype rather than waiting for perfect specs: build something first, then update and finalize the specs based on observed behavior, and lead implementation across platformsLeading quality, measurement, and release phases Establish reliable measurement through event design, logging, and dashboards, while also designing quality standards and phased rollout plansMaking technical design decisions autonomously Independently make decisions on architecture, APIs, data design, security, and operational considerations, explaining trade-offs in a business context to d