株式会社LegalOn Technologiesの
TECH-110/EN Software Engineer, Backend - AI Agentの求人

募集概要

We are 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 have been focused on building AI-powered legal services. We have raised a total of approximately $200 million across multiple funding rounds and are growing at an extraordinary pace. In 2022, we established a U.S. headquarters to accelerate our global expansion. Today, our flagship product, LegalOn: World Leading Legal AI, is available not only in Japan, but also in the U.S. and the U.K. We are also boldly exploring new business areas. In January 2025, we expanded our scope across the corporate domain with the launch of CorporateOn, our AI Counsel product. Our solutions incorporate cutting-edge technologies in natural language processing and machine learning, including large language models (LLMs), a structured Legal Document Graph for organizing legal information, and autonomous AI agents capable of planning and executing legal tasks. In addition, we have formed a strategic partnership with OpenAI, enabling us to deliver advanced user experiences and innovative legal solutions as a leader in the legal AI space. For more details about our company, products, and development organization: https://legalforce-recruit.notion.site/LegalOn-Technologies-3e114a8aecfb410a96424e34a0ed8bd6 We are currently building a new product from the ground up that centers around AI Agents, delivering a radically new user experience. AI Agents are intelligent tools that understand users' natural language, create plans, and autonomously execute tasks to completion on their behalf. This product is being built from scratch, and the backend plays a critical role in orchestrating LLMs, tools(MCP), custom workflows, agent's long/short term memory, and user data with reliability and flexibility. To succeed, we need backend engineers who are not only technically strong but also product-minded and eager to tackle ambitious challenges alongside a cross-functional team. If you’re excited about shaping the backend of intelligent, task-completing agents - while balancing speed, scale, and safety - we’d love to hear from you. 【Key Responsibilities】 You will take ownership of designing and developing the backend architecture for our AI Agent product. This includes implementing APIs that interface with agent engine, managing session storage, message queues, database and other backend components, ensuring robustness of task execution, and designing data models that reflect real-world agent behavior.As an early team member, you'll also be deeply involved in architecture design, technology selection, and team culture. This is not a “build to spec” role—you’ll collaborate closely with designers, product managers, and AI engineers to iterate quickly and deliver user-impactful features. ■What Mission and Challenges you’ll take on - Designing and developing core features to realize AI agents that can complete real-world tasks—not just engage in conversation - Designing and building a backend foundation from scratch, free from existing constraints and with a clear vision for the product’s future ■What You’ll Do - Design and develop backend systems for a new AI Agent product from the ground up - Build APIs, task orchestration systems, and data models that support dynamic, goal-driven agent behavior - Integrate external tools and internal components (LLMs, workflow engines, etc.) - Ensure reliability, observability, performance, and scalability in production environments - Contribute to automation, testing, documentation, and engineering process improvement - Mentor junior engineers and contribute to team growth ■What Makes This Job Rewarding - Collaborate as equals with product managers and business stakeholders as part of a unified team - Gain valuable decision-making experience in a fast-growing company where you will be trusted with significant ownership and influence over business, technical, and process direction 【Development Environment / Tools】 Backend：Python, Go ▼We have compiled information about development environments and tools for our other products on Notion. https://legalforce-recruit.notion.site/LegalOn-Technologies-f5ebe38a6009428ab0fb1714efd3c90a

必須スキル

Required Skills / Qualifications - 3+ years of professional experience in backend development for web applications - Proficiency in programming languages such as Python, TypeScript, or Go - Experience designing and implementing APIs (e.g., REST, WebSocket) - Experience in designing and operating databases such as PostgreSQL, MySQL, or MongoDB - Basic knowledge of microservices, distributed systems, and asynchronous processing - Ability to work autonomously in collaboration with cross-functional roles such as product managers, designers, and AI engineers - Japanese language proficiency equivalent to JLPT N2 or above - Interviews will be conducted in Japanese - Only the first technical interview can optionally be conducted in English

歓迎スキル

Preferred Skills / Qualifications - Foundational understanding of LLMs or AI Agents, or experience developing related products - Experience in session management, job scheduling, and queue processing (e.g., Redis, Kafka, SQS) - Knowledge of infrastructure tools such as Docker and Kubernetes - Experience with CI/CD pipelines, test automation, and observability/monitoring tools - Experience in designing and reviewing systems with a focus on security and scalability - Hands-on experience in early-stage startups or new business development environments - Strong communication skills, with the ability to work effectively across diverse cultures in both English and Japanese

求める人物像

Ideal Candidate - Proactive communicator who collaborates well and thinks through the why and what behind every development effort - Flexible thinker who solves problems beyond their comfort zone or specialty area - Respectful and team-oriented contributor who works for the success of others, not just their own - Growth-oriented individual who is eager to learn and willing to put in the effort to improve

応募概要

給与: 7.7 to 12million yen per year
勤務地: 19F, Shibuya Sakura Stage SHIBUYA TOWER, 1-1 Sakuragaoka-cho, Shibuya-ku, Tokyo 150-6219, Japan This is not a fully remote position. Hybrid work is required, and visa support is available.
雇用形態: Full-time
勤務体系: - Working hours: Full flex system without core hours - Overtime work beyond designated working hours: Yes - Break time: 1 hour
試用期間: 3 months
福利厚生: - Holidays: Saturdays, Sundays, and National holidays - Time Off: Year-end and new year holidays, Paid leave, Special leave (Sick leave, Work-life balance holiday, Birthday holiday), Maternity leave, Childcare leave, Nursing leave - Social Insurance: Health insurance, Employee pension insurance, Unemployment insurance, Worker's compensation insurance - Language learning support - Technical book purchase support - Influenza vaccination support - No smoking indoors (smoking room available in the building) - Side jobs are allowed upon request