Lead Fullstack Engineer (Core API Team)

**About the company:** Mico Minato-ku, Tokyo We offer multiple products that deliver conversational experiences, including MicoCloud, a platform that is used by over 1,000 clients to reach over 29 million people. **Responsibilities:** Stabilizing the Mico Engage AI delivery infrastructure: Build and improve the infrastructure that enables stable, large-scale delivery even for clients with high user volumes. Developing new features: Implement product-enhancing features based on our product roadmap. Customer-driven development: Build high-impact, reusable features based on needs identified through Customer Success activities. Requirements 5+ years of hands-on experience in system development Experience developing with TypeScript and React Full-stack engineering experience (both frontend and backend) Ability to independently handle the full development cycle from requirements definition to release 2+ years of code review experience Ability to write test code and contribute to improving product quality Experience in technical decision-making (evaluating technical requirements, cost, and maintainability to make balanced decisions) 2+ years of experience leading development as a technical lead (teams of 5+ members) Experience designing REST APIs Business-level proficiency in Japanese Nice to haves While not specifically required, tell us if you have any of the following. Experience developing with Go Experience designing systems using Domain-Driven Design or Clean Architecture Experience developing gRPC APIs Ability to effectively leverage AI to improve development speed and quality, and to document/share best practices for AI utilization Experience developing with Next.js Experience building CI/CD pipelines Experience in infrastructure setup (AWS, Docker, etc.) Business-level proficiency in English Compensation ¥7,000,000 ~ ¥10,000,000 annually. **Requirements:** 5+ years of hands-on experience in system development Experience developing with TypeScript and React Full-stack engineering experience (both frontend and backend) Ability to independently handle the full development cycle from requirements definition to release 2+ years of code review experience Ability to write test code and contribute to improving product quality Experience in technical decision-making (evaluating technical requirements, cost, and maintainability to make balanced decisions) 2+ years of experience leading development as a technical lead (teams of 5+ members) Experience designing REST APIs Business-level proficiency in Japanese **Nice to have:** While not specifically required, tell us if you have any of the following. Experience developing with Go Experience designing systems using Domain-Driven Design or Clean Architecture Experience developing gRPC APIs Ability to effectively leverage AI to improve development speed and quality, and to document/share best practices for AI utilization Experience developing with Next.js Experience building CI/CD pipelines Experience in infrastructure setup (AWS, Docker, etc.) Business-level proficiency in English **Compensation:** ¥7,000,000 ~ ¥10,000,000 annually.