Software Engineer - Experimentation System - Mercari

Overview

Employment Status: Full-time
Work Hours: Full Flextime (no core time)
Office: Roppongi (Hybrid)
Location: Minato City, Tokyo, Japan

Team Mission

Within the Strategic Experimentation & Analytics (SEA) team, we are responsible for the administration, operation, and optimization of the Experimentation Platform—a system that enables anyone at Mercari to perform A/B tests and experiments and safely and gradually roll out new features. The team oversees the Experimentation Platform and Feature Flags systems across both production and development, handling incident response, demos, and roadmap planning while coordinating A/B testing and feature rollouts.

• Everyone can learn and acquire empirical knowledge about customer behavior and our service domain
• Anyone at Mercari can run experiments at scale
• Everyone can understand and trust reproducible experiments
• All product changes can be rolled out or rolled back quickly and safely via Feature Flags

Work Responsibilities

• Continuously improve the system for access control, resource allocation, cost optimization, and usability to deliver sustained value to engineering and product teams.
• Design and maintain a scalable distributed system
• Implement new features on an existing code base
• Scale the current product to handle 10x load
• Design and implement agentic workflows

Unique Challenges

• Architecting for modern AI workflows. As the organization transitions to becoming AI-native, you will be instrumental in designing and building the systems that highly efficiently support new use cases, such as automated configuration, control, and data utilization via AI agents.
• Ability to design and maintain a scalable distributed system
• Operate and debug via observability metrics and Kubernetes
• Basic familiarity with cloud-based databases and tools (Google Cloud, BigQuery, Redis, etc)
• Understanding of stateless API design and protocols (gRPC)
• Define, implement, test, and deploy core features in an existing code base independently
• Communicate effectively with technical and non-technical stakeholders
• Quickly acquire a solid foundation in Software Engineering concepts such as Domain Driven Design, Event Sourcing, Service Oriented Architecture

Qualifications

Passionate about building tools for developers, with a strong ability to collaborate with the team to identify and implement features.

Required Experience/Skills

• Go, Python, Typescript
• Good CS fundamental
• Experience with Cloud technologies
• communicate effectively with technical and non-technical stake-holders
• Ability to quickly acquire a solid foundation in Software Engineering concepts such as Domain Driven Design, Event Sourcing, Service Oriented Architecture

Preferred Experience/Skills

• Bazel, Cuelang, Terraform, GCP, Kubernetes
• Implementing parsers and virtual machines
• Memory allocation optimization

Language

• Japanese: A2
• English: B2 and above

(For details about CEFR, see here.)