Backend Developer (Ruby)

freeC's Client

• Maintain and improve an existing Japanese Applicant Tracking System (ATS).
• Develop, fix, and update backend features using Ruby on Rails.
• Support system optimization work, especially around performance, database usage, and maintainability.
• Work with senior developers on ongoing upgrade and modernization tasks.
• Investigate issues, implement fixes, and help keep the system stable in production.
• Contribute to code reviews, testing, and day-to-day team development activities.

Job requirement

• At least 3 years of professional experience with Ruby on Rails development.
• Experience maintaining and enhancing an existing web system or business application.
• Basic working knowledge of relational databases such as PostgreSQL, including writing and improving SQL queries when needed.
• Ability to read existing code, understand business logic, and implement changes carefully.
• Comfortable working as part of a team and collaborating with senior developers.
• Practical problem-solving skills and a steady, responsible approach to development work.

Preferred qualifications

• Experience with system performance improvement or backend optimization.
• Experience with Ruby or Rails version upgrades.
• Experience working on internal business systems or operational platforms.

• Hybrid working and flexible working hours (8:30 AM - 9:30 AM + 8 hours from Monday to Friday).
• Year-end reward (based on company regulations and business situation).
• Premium Health Care (applied for full-fledged employees).
• Annual Performance and Salary Review.
• 15 annual leave days a year.
• Laptop provided.
• Mandatory insurance: based on company regulations, the probationary period is excluded. 
• Happy Hour, Company Trip, Year End Party, Events, etc.
• Modern office and a great working environment