Software Engineer - Backend

This role sits at the intersection of core platform engineering and new business development within a global leader in AI-powered domain expertise services. You will be responsible for building and scaling backend systems that extract and accumulate useful knowledge from diverse data sources, as well as developing high-quality software for new, high-impact business initiatives from the 0→1 phase.

Key Responsibilities

Formulate development plans, design, implement, test, and operate web applications and backend APIs for both internal knowledge extraction platforms and new customer-facing products. Modeling & Architecture: Perform domain and data modeling focused on future scalability and product evolution. Design architectures that balance high quality with high development productivity.

Engineering Productivity: Build systems to enhance developer experience, including schema-driven development, library creation, CI/CD pipelines, and automated testing. Continuous Improvement: Lead various automation efforts, establish operational processes, and maintain technical documentation to improve team productivity and product quality.

Innovation & Technical Selection: Take responsibility for technology selection and the stable delivery of high-quality software, balancing business growth with technical investment and debt management. Leadership & Mentoring: Provide guidance, mentoring, and coaching to team members as needed to foster a high-performing engineering culture.

Requirements

Experience: 5+ years of professional experience in web system development and maintenance. Programming: Practical development experience with at least one (preferably multiple) major languages such as Python, Java, Go, or Rust. Cloud & Infrastructure: Hands-on experience designing and building systems using AWS, GCP, or Azure.

Containerization: Practical experience with Docker and other container technologies. Database Management: Experience in development and operation using Relational Databases (RDB). Code Quality: Proven experience in initiatives to improve code quality and team productivity, including technical selection and implementation.

Language: Business-level Japanese proficiency (Equivalent to JLPT N2 and above); interviews will be conducted in Japanese. Preferred Experiences: Architectural Patterns: Practical experience with DDD (Domain-Driven Design) or Clean Architecture. Modern Infrastructure: Experience with Kubernetes, Terraform (IaC), and Microservices architecture.

Technical Depth: Knowledge of I/O and algorithm optimization, performance tuning, and web security best practices. Specialized Engineering: Experience with Natural Language Processing (NLP), parsing, data structures, and data visualization. Frontend Exposure: Experience with modern frontend frameworks such as React, Vue, or Angular.

Global Collaboration: High communication skills to collaborate with diverse team members across different cultural backgrounds (fluency in both English and Japanese is a significant plus).

Benefits

Schedule: Full flextime system (no core time) or a discretionary work system. Location: Tokyo (specific area hidden); full remote work is generally not available, though flexible arrangements may be discussed for new projects. Holidays: 120+ days off per year, including a complete five-day work week (Sat/Sun off) and public holidays.

Vacations: Paid leave (granted upon joining), New Year’s holidays, and special leaves (sick leave, birthday leave, work-life balance leave, and parental leave).

Compensation

& Perks: Salary Range: Determined by experience and skills AI Tools: Full distribution of advanced AI tools to all employees (e.g., ChatGPT Enterprise, Gemini for Google Workspace, etc.) Developer Support: Access to cutting-edge development assistance tools (e.g., Cursor, GitHub Copilot, Devin, etc.) Growth Support: Dedicated budget for self-improvement and language learning assistance.

Social & Health: Complete social insurance, influenza vaccination assistance, and employee stock ownership programs. Side Jobs: Allowed with prior permission.