AI Engineer (Tech Lead)

The role leads AI product development, AI project delivery, and overall management of the AI team for an in-house SaaS product. Responsibilities include designing and building LLM applications and AI Agents for existing and new products, selecting technologies, and implementing them in production. The role designs systems that address hallucinations, robust numerical validation, and harness engineering for products handling management figures. It also builds a robust AI Agent platform with data traceability and security, including multi-tenancy considerations. The AI technical lead translates business problems into AI implementations with business leaders, the product manager, and development teams, and works with C-level management on roadmaps and technical strategy.

The product is a cloud management-control system that collects, integrates, and centrally manages financial figures and KPI budgets, forecasts, and actuals, supporting advanced analysis. It began in 2020, and the company has pursued a multi-product strategy since 2023, providing five products and services. The company is developing an AI-native platform from the ground up, combining general-purpose LLMs and an AI Agent foundation. The work addresses re-architecture for multi-tenancy, low latency under high data volumes and traffic, and technical debt. The Agent foundation uses microservices and includes work on LLM observability. The architecture is designed to avoid dependence on a specific LLM and to support switching among multiple models. The team builds its own foundation for domain-optimized context injection rather than using external agent services such as Amazon Bedrock as-is.

Required qualifications include strong curiosity about advanced technology and rapidly changing trends, the ability to learn independently and quickly, end-to-end ownership from problem definition and system design through hands-on implementation and code contributions, experience developing and operating applications using LLM or AI, and experience building a microservices architecture or data pipeline. Desired qualifications include experience launching or leading an AI department or AI product, including either 0-to-1 or 1-to-10 work, and experience managing AI projects with development teams or vendors. The role calls for understanding both technology and business, converting abstract issues into concrete action, improving decision-making with AI, proposing and executing technical solutions with stakeholders, and structuring changing situations into repeatable systems.

This is a full-time permanent position with a three-month probationary period, extendable to six months. Annual compensation is JPY 10,000,000 to JPY 20,000,000, determined partly by experience and skills. The stated examples include fixed overtime for 60 hours per month, with additional payment for hours beyond the fixed overtime. Working hours are 10:00–19:00 with a one-hour break and flextime with core hours from 10:00–15:00. The workplace is in Mita, Minato, Tokyo; the stated location-change range includes places where remote work is performed. Holidays are Saturdays, Sundays, public holidays, and December 28 through January 3. Paid leave is granted at 10 days upon joining, with condolence, child nursing, caregiving, and menstrual leave also available. Benefits include company-leased housing, support for PC-related equipment, and a corporate defined-contribution pension plan. Insurance includes health, employees’ pension, employment, and workers’ compensation. Duties may be changed to company-designated work, and the work location may be changed to company-designated locations.