Senior Software Engineer, AI Agent & Search - LegalOn

As LLMs and AI agents continue to reshape product experiences, search and recommendation are rapidly becoming core technologies that enable AI agents to perform complex professional tasks, rather than simply standalone features. In our global product “LegalOn,” the search and recommendation platform is also one of the most mission-critical systems.

In this role, you will join a team responsible for improving specific areas of the user experience in “LegalOn.” Leveraging your expertise in search and recommendation, you will play a core role in designing and developing AI agent features to deliver highly valuable product experiences for users. We welcome people who are genuinely interested in search and generative AI technologies and who enjoy shaping user experiences through collaboration.

The backend you’ll be developing is written in Go and Python.

Responsibilities

• Leverage expertise in search, recommendation, and AI to maximize user value as part of a team responsible for improving specific areas of the user experience
• Collaborate with product managers and related teams to explore various possibilities for what features to deliver to customers
• Drive concrete and actionable development plans to ensure the successful delivery of product features
• Contribute to broader product development beyond search and recommendation to enhance the overall user experience
• Mentor team members in designing sustainable and highly maintainable software systems
• Design, build, and deliver a wide range of search, recommendation, and Agent features/APIs
• Integrate LLM-powered applications with search and recommendation features to expand product capabilities
• Proactively maintain and operate search and recommendation systems to ensure high availability and performance
• Collaborate cross-functionally to investigate production issues in search, recommendation, and Agent systems, establish quantitative evaluation metrics, and drive continuous improvements
• Develop a deep understanding of user behavior regarding search and recommendation to contribute to broader product development and ensure a cohesive user experience

Requirements

• 5+ years experience in software engineering
• Experience in one or more of the following
  • Experience developing AI agent features leveraging LLMs
  • Experience developing large-scale search or recommendation systems
  • Experience developing or improving machine learning models
• Experience designing and developing production-grade backend services using Python or Go
• Experience improving development processes by leveraging AI tools
• Knowledge of data structures and algorithms
• Hands-on expertise in building highly reliable and performant web backend systems
• Hands-on experience with one of the Cloud Infrastructure Services: AWS, GCP, or Azure
• Business-level communication skills in Japanese (JLPT N1 or equivalent)

Nice to haves

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

• MS or Ph.D. degrees in Computer Science, Mathematics, or other technology-related majors.
• Hands-on experience in Apache Lucene, Elasticsearch, or Solr.
• Hands-on experience in developing Agent applications and related component technologies such as LangChain, Ragas, LlamaIndex, etc.
• Hands-on experience in machine learning and natural language processing.
• Experience mentoring/training junior engineers.
• Leadership experience in large-scale projects or teams (10+ members) with a proven track record of delivering results
• Strong communication skills, with the ability to work effectively across diverse cultures in both English and Japanese
• Experience contributing to product features across multiple domains or technology areas, beyond a single specialization