Software Engineer, MAPI at Mercari

Location: Tokyo
Type: Full-time
Posted: May 22, 2026

Description

Mercari is seeking a full-time Software Engineer specializing in MAPI (Monolithic API) migration and maintenance. The role involves transitioning a PHP-based service to Go, collaborating with various teams, supporting existing PHP frameworks, and ensuring the stability of the current service. Key challenges include minimizing disruption during migration, operating a high-traffic service, gaining deep insights into the C2C platform, and managing a complex migration project.

Required Skills

backend engineering
on-call for mission-critical high-traffic backend systems
reliability and stability
programming languages such as PHP and Go
Kubernetes and Terraform
Strong communication skills
understand and align with Mercari's technical direction
service growth and scalability
software archaeology
observability for large-scale monolith systems

Additional Information

Required Previous Experiences: Experience in backend engineering for mission-critical services.
Hands-on experience being on-call for mission-critical high-traffic backend systems, with a focus on ensuring reliability and stability.
Preferred Qualifications: Expertise in "software archaeology," with the ability to analyze and understand the history and evolution of legacy codebases and resources.
Familiarity with implementing and maintaining observability for large-scale monolith systems to ensure service reliability.

About Mercari

Mercari

Discover deals on everything from secondhand fashion to pre-owned collectibles, electronics, books & more on Mercari. Your go-to marketplace for hassle-free selling and deals.