AI Engineer - DealOn

LegalOn Technologies Shibuya-ku, Tokyo April 14 2026
  • 💴 ¥7.7M ~ ¥15M annually
  • 🏡
    Partially remote
  • 🌏
    Apply from abroad
    Relocate to Japan
  • 💬
    Fluent Japanese
    No English required
  • 🧪
    Intermediate to senior levels
    5+ years experience required
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About LegalOn Technologies

LegalOn Technologies Shibuya-ku, Tokyo

LegalOn Technologies is a global legal AI company that combines advanced expertise in artificial intelligence with deep knowledge of law and contracts. Since our founding in 2017, we’ve been focused on building AI-powered legal services that help legal and business teams work faster and more confidently.

Key benefits

  • Collaborative, Respect-Driven Culture
  • Comfortable and Supportive Work Environment
  • Cutting-Edge Technology and Expert Colleagues

About the position

Responsibilities

  • Own the design, development, and operation of AI-native features centered on RAG, LLMs, and AI agents, going beyond model implementation to deeply integrate with UI/UX and business workflows to deliver truly usable AI experiences
  • Lead end-to-end decision-making across model selection, inference architecture, RAG design, and agent design based on specific use cases, balancing both quality and speed
  • Design and implement robust operational frameworks—including evaluation, monitoring, logging, and cost optimization—to continuously improve and maintain a reliable and trustworthy AI experience
  • Design and implement highly reliable agent-based LLM workflows for production environments
  • Build execution infrastructure for AI agents by integrating with external services and internal APIs
  • Evaluate and select appropriate external models, frameworks, and services based on use case fit
  • Translate user needs into concrete requirements through stakeholder discussions, and collaborate cross-functionally to design optimal agent-based solutions
  • Establish testing frameworks and monitoring systems to evaluate agent performance, and visualize key metrics
  • Define development processes and quality standards through code reviews and comprehensive documentation
  • Identify and address technical challenges to ensure the accuracy, reliability, performance, and scalability of AI systems, driving continuous improvement

Requirements

  • 5+ years of development experience in at least one of the following: Python, TypeScript, or Go
  • Hands-on experience building applications using LLM APIs (e.g., OpenAI, Anthropic, Google Gemini, Mistral)
  • Practical experience developing AI agents (e.g., LangChain, CrewAI, OpenAI Agents SDK, Google ADK, MCP) and working with context engineering
  • Experience designing and implementing RAG systems, including embeddings, vector databases, and retrieval algorithms
  • Experience improving generation quality through prompt optimization and the design of evaluation metrics
  • Solid foundation in natural language processing (NLP) and experience building data pipelines
  • Japanese proficiency equivalent to JLPT N1

Nice to haves

While not specifically required, tell us if you have any of the following.

  • Experience building and operating search infrastructure using Elasticsearch, OpenSearch, Vespa, or similar technologies
  • Experience designing systems that integrate knowledge graphs or structured data with RAG
  • Experience designing and operating systems in cloud environments such as AWS, Google Cloud, or Azure
  • Experience preprocessing and normalizing unstructured text data, such as customer emails, FAQs, and product documentation

Compensation

¥7,700,000 ~ ¥15,000,000 annually.

Hiring Process

  1. 1

    Resume Screening

  2. 2

    Casual Interview

    We offer the option to start with a casual interview, depending on your preference.

  3. 3

    Interviews/Aptitude Test

    We will conduct a technical interview, a behavioral interview, and an executive interview. The number of interviews may vary depending on the position and may change during the selection process. We use external aptitude tests, such as SPI and reference checks.

  4. 4

    Offer Meeting

DO YOU NEED MORE INFO?
ASK A QUESTION

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