AI Engineer

This role focuses on building next-generation AI-native features centered on RAG, LLMs, and AI Agents. As part of a global team, you will move beyond simple model implementation to deeply integrate AI with UI/UX and complex business workflows, ensuring a high-quality, reliable user experience.

Responsibilities

Own the design, development, and operation of AI features, ensuring they are deeply integrated into business workflows to deliver usable AI experiences. Technical Leadership: Lead decision-making regarding model selection, inference architecture, RAG design, and agent workflows based on specific use cases, balancing quality with speed.

Agentic Workflows: Design and implement highly reliable agent-based LLM workflows and build the necessary execution infrastructure by integrating external services and internal APIs. Operational Frameworks: Design and implement robust frameworks for evaluation, monitoring, logging, and cost optimization to maintain a trustworthy AI experience.

Cross-Functional Collaboration: Translate user needs into concrete requirements through stakeholder discussions and collaborate cross-functionally to design optimal solutions. Quality Standards: Establish development processes, testing frameworks, and documentation standards while providing code reviews to ensure system scalability and accuracy.

Requirements

Development Experience: 5+ years of experience in at least one of the following: Python, TypeScript, or Go. LLM Expertise: Hands-on experience building applications using LLM APIs (e.g., OpenAI, Anthropic, Google Gemini). AI Agents & RAG: Practical experience with AI agent frameworks (e.g., Lang. Chain, CrewAI, Agents SDK) and designing RAG systems, including embedding and vector databases.

Context Engineering: Experience improving generation quality through prompt optimization and the design of specific evaluation metrics. NLP Foundations: Solid foundation in natural language processing (NLP) and experience building data pipelines. Language Proficiency: Japanese proficiency equivalent to JLPT N1.

Preferred Skills

Experience with search infrastructure such as Elasticsearch, Open. Search, or Vespa. System design experience integrating knowledge graphs or structured data with RAG. Practical experience designing and operating systems in cloud environments (AWS, Google Cloud, or Azure). Expertise in preprocessing and normalizing unstructured text data (e.

g., emails, FAQs, and documentation).

Benefits

Work Style: Hybrid work is required (not fully remote); visa support is available. Flexibility: Full flex system without core hours. Holidays: Weekends, national holidays, and year-end/New Year holidays off. Professional Growth & Environment: AI & Developer Tools: Access to a premium suite of tools including ChatGPT Enterprise, Gemini for Google Workspace, Claude Code, Cursor, and GitHub Copilot.

Equipment: Choice of Mac or Windows laptop (Mac with US keyboard available). Development Support: Self-development budget for books, online courses, and certifications, plus language learning support. Side Jobs: Permitted with prior approval. Welfare & Leave: Special Leave: Sick leave, work-life balance leave, and birthday leave.

Family Support: Maternity, childcare, and nursing care leave. Insurance & Programs: Complete social insurance, influenza vaccination support, and an employee stock ownership program.