株式会社LegalOn TechnologiesのDZSA-01-Software Engineer - Searchの求人

LegalOn Technologies is a global leader in legal AI solutions, trusted by more than 8,000 companies and law firms worldwide. The company empowers legal teams to review and negotiate contracts faster, with greater accuracy and confidence. Operating across Japan, the United States, and Europe, LegalOn is the first AI company from Japan to surpass ¥10 billion in annual recurring revenue (ARR) and has raised over $200M from leading investors including SoftBank and Goldman Sachs. It also has one of the largest and most global AI teams of any startups in Japan. In 2025, LegalOn achieved its first M&A by welcoming Germany's Fides Technology into the group, further accelerating global expansion. LegalOn combines LLMs, intelligent Agents and intelligent AI-driven workflows. Beyond legal, the company now offers specialized AI solutions including "CorporateOn," "CXOn," and "DealOn" to support diverse business domains requiring high expertise. In partnership with OpenAI, the company is redefining the legal AI landscape and developing innovative solutions for the future of professional work.

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

Key Responsibilities

LegalOn Technologies is a leading company in AI product development, and our search and recommendation platform is one of the most important, mission-critical systems behind the products we deliver.
In particular, as search has become increasingly essential in recent years as a key enabling technology that expands the capabilities of LLM-powered applications, we are looking for a Software Engineer with a strong passion for technology.

In this role, you will contribute to the development of our global product “LegalOn” as an engineer with deep expertise in search and recommendation, tackling complex challenges and helping evolve the product into a technically advanced and refined experience for users.

What Mission and Challenges You’ll Take On

• Collaborate with product managers 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

• Design, build, and deliver a wide range of search, recommendation, and Agent features/APIs.
• Implement functional extensions such as integration between our products and search/recommendation features.
• Proactively maintain and operate search and recommendation features/APIs.
• Collaborate with team members and other teams to investigate search/recommendation accuracy issues in production systems, establish quantitative evaluation metrics, and drive improvements.

• 3+ years of experience in search or software engineering.
• Experience developing web applications or data processing platforms using Python.
• A proactive attitude toward adopting AI-powered development processes and tools, regardless of prior experience.
• Knowledge of data structures and algorithms.
• Hands-on experience in web backend system design.
• Hands-on experience with one or more cloud infrastructure services such as AWS, GCP, or Azure.
• Ability to communicate in Japanese (JLPT N2 or equivalent experience)

• 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 LangGraph, Ragas, LlamaIndex, etc.
• Hands-on experience in machine learning and natural language processing.
• Experience mentoring/training junior engineers.
• A proactive attitude towards learning and adopting new technologies, including AI-powered efficient development and task execution
• 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