Web Application Engineer (IR Domain LLM New Product)Translated from Japanese

▼Job Description Background We are currently driving the development of a new product utilizing LLM within corporate IR departments. This service had a closed release in July 2025. Customers are already steadily increasing, and it is expected to become a new pillar of our business. We are looking for a full-stack engineer who can lead the product's growth phase, consistently handle product design, development, and operation while integrating business strategy and technical strategy at a high level. We are seeking a strong leader who will drive fundamental customer problem-solving and business growth by leveraging cutting-edge generative AI technology. Job Overview Towards the realization of our mission, "Let's create a good economy," we are developing a product that streamlines and enhances IR department operations. As a full-stack engineer in the new business team, you will be responsible for product design, development, and operation. This initiative is driven by a lean, elite team consisting of a Development Lead, 2 Engineers, 1 PdM, and 1 Designer. You will engage in product development with a technical perspective on business strategy to maximize customer value in the mid-to-long term. Your specific mission will be to collaborate with the PdM to handle everything from discovery to delivery, leading architectural design with future scalability and maintainability in mind, improving development processes, and maximizing business outcomes through the product. Responsibilities Lead architecture design and technology selection Design and make technical decisions for an architecture that supports future scalability and continuous product growth. Design and implement core features utilizing LLM Design and implement prompt and context engineering using multimodal data for the product's core. Continuous feature development with Go (backend) x Next.js (frontend) Take ownership of the entire development process Lead efforts to improve the productivity and accelerate the output speed of the entire development team. Discovery with PdM (requirements gathering, specification review, definition) Deeply understand business strategy and requirements, and explore "What are the fundamental customer challenges?" in collaboration with the PdM. Ensure and improve technical quality Promote code reviews, performance optimization, and resolution of technical debt. ▼Required Skills/Experience Experience leading technical decision-making and promotion that impacts organizations larger than your team. Experience considering technical strategy from management and business strategy. Experience in improving team processes, enablement, and various automation efforts to enhance team productivity. 5+ years of experience in web application design and implementation. Development experience using strongly-typed languages such as Java, Go, or TypeScript. Proficiency or strong interest in technologies for creating high-quality products, such as TDD and DDD. Technical lead and code review experience in small teams. ▼Preferred Skills/Experience Experience involved in launching and growing new businesses from scratch. Experience with PoCs for products incorporating LLM / Generative AI. Experience designing and implementing integrations with external SaaS APIs such as Salesforce. ▼Ideal Candidate Profile Someone who is execution-first, pursuing fundamental customer value and able to iterate quickly on hypotheses. Someone with leadership skills to lead the development team from requirements definition to release. Someone who actively learns the latest generative AI technologies and can translate them into product value. Someone willing to commit to business growth beyond direct development, such as through recruitment, technical evangelism, or customer interviews. ▼Job Highlights [Autonomy as a Full-time Engineer in a Lean, Elite Team] Experience a wide range of technical decision-making related to product development, including technology selection, architecture design, development process construction, and mid-to-long-term organizational structure development. [Growth Experience in the 0 to 1 Phase] Practical experience in growing a product immediately after MVP release, iterating quickly on hypotheses with the PdM, towards achieving Product-Market Fit (PMF). [Technical Experience in LLM Practical Application] Practical experience applying LLM in a real product, delivering valuable output to users by leveraging data in IR operations. ▼Development Environment Server-side Go Frontend React / Next.js / TypeScript Infrastructure AWS / Terraform / Fargate / ECR DB Aurora PostgreSQL Testing Tools Datadog Synthetics / Playwright Tools & Services Used Slack / Gather / Figma / Findy team＋ / Notion / Miro / diaglams.net / Cursor ▼Employment Type Full-time (No fixed term) ▼Probationary Period 3 months (up to 6 months) ▼Salary Annual salary: ¥7,000,000 - ¥20,000,000 ▼Minimum Annual Salary (in 10,000 JPY) 700 ▼Maximum Annual Salary (in 10,000 JPY) 2000 ▼Work Location 9F, Kokusai Kogyo Mita 2nd Bldg., 3-11-24 Mita, Minato-ku, Tokyo 108-0073 (Remote work is also possible) ▼Working Hours 10:00 - 19:00 ▼Break Time 1 hour ▼Overtime Work Available ▼Holidays, Paid Leave, Special Leave Complete two-day weekend system - Saturdays, Sundays, National Holidays, Year-end holidays (12/28 - 1/3) Leave - Annual paid leave (10 days granted upon joining), congratulatory/condolence leave, childcare leave, family care leave, menstrual leave, etc. ▼Benefits - Leased company housing system - Subsidy for PC peripherals - Corporate Defined Contribution pension plan, etc. ▼Insurance Enrollment Health Insurance, Employee Pension Insurance, Employment Insurance, Industrial Accident Insurance ▼Measures to Prevent Passive Smoking at the Workplace No smoking within the premises (smoking area available outdoors)