DZSA-01-Software Engineer - AI Agent & Search

We are a global leading company providing Professional AI — products that combine deep domain expertise with advanced AI.
Since our founding in 2017, we have focused on developing AI-powered legal technology, raising a total of approximately JPY 28.6 billion to date. In 2022, we established our U.S. entity, and in 2025, we accelerated our global expansion further through our first M&A, welcoming Germany-based Fides Technology into our group.
Our flagship product, LegalOn, is currently available in Japan, the United States, and the United Kingdom. In September 2025, just six and a half years after launch, LegalOn surpassed JPY 10 billion in ARR. Beyond legal, we are expanding into other highly specialized domains with products such as CXOn, DealOn, and GovernOn, leveraging AI to support complex professional work.
Through our strategic partnership with OpenAI, we incorporate cutting-edge technologies such as AI agents into our product development. By delivering solutions that address a wide range of business challenges, we empower our customers to achieve better outcomes.

For more details about our company, products, and development organization:
https://legalforce-recruit.notion.site/LegalOn-Technologies-Candidate-Handbook-17d82a58637480d2836ae138e5b5ee95

Key Responsibilities

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.

What Mission and Challenges You’ll Take On

• 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
• Follow the direction set by the Tech Lead or Project Leader, break down development tasks, and execute the development plan. For smaller projects or sub-projects, take on the role of project leader, creating a practical development plan for delivery and taking responsibility for its execution.

What You’ll Do

• Play a core role in the design, development, and delivery of AI agent features and related APIs
• Leverage expertise in search and recommendation to design, develop, and operate AI agent, search, and recommendation features for the user experience areas you own
• Collaborate with team members and cross-functional partners to investigate quality issues related to AI agent and search/recommendation systems affecting the user experience, define quantitative evaluation metrics, and drive improvements
• Understand the implementation of the search platform and leverage that knowledge in development, while responding to issues within your area of ownership as needed

• 3+ years of experience in web backend development or equivalent software engineering
• Experience in product development using Python or other major backend programming languages
• Hands-on experience with one or more cloud infrastructure services such as AWS, Google Cloud, or Azure
• A proactive attitude toward adopting AI-powered development processes and tools, regardless of prior experience
• Ability to communicate in Japanese (JLPT N2 or equivalent experience)

• An MS or Ph.D. in Computer Science, Mathematics, or a related technical field
• Experience designing and developing production-grade backend services using Go
• Experience developing and operating large-scale products built on a microservices architecture
• Hands-on experience in Apache Lucene, Elasticsearch, or Solr
• Hands-on experience in developing Agent applications and related component technologies such as LangGraph, Ragas, LlamaIndex, etc
• Experience mentoring/training junior engineers
• Strong communication skills, with the ability to work effectively across diverse cultures in both English and Japanese
• Experience in product development spanning multiple domains and technology areas, beyond a single area of expertise