Hiroki Otani

Background

About Hiroki Otani

About Product-oriented software engineer with a strong backend focus, experienced in building and evolving production web products using Ruby on Rails. I work at the intersection of engineering, product requirements, and business logic—translating ambiguous needs into clear domain models and maintainable systems. Rather than optimizing only for implementation speed, I prioritize long-term product sustainability, clarity of ownership, and realistic system boundaries. My work includes- Shaping product requirements through technical discussion and domain modeling - Designing APIs and data models that reflect real business rules - Incrementally improving existing systems through refactoring and test coverage - Operating and improving cloud-based services in production environments I enjoy environments where engineers are expected to think beyond tickets and contribute to product decisions, trade-offs, and delivery strategy.# Experience Product Engineer / Backend Engineer Japan-based Web Company 2023 – Present - Contributed to product design by clarifying requirements and edge cases before implementation - Designed and evolved domain models to handle complex business states and transitions - Built and maintained backend features using Ruby on Rails - Implemented APIs supporting frontend and internal product workflows - Refactored legacy features to improve correctness, readability, and long-term maintainability - Improved development feedback loops via automated testing and linting - Deployed and operated services on Google Cloud Platform (Cloud Run, Cloud Build)- Worked in a team environment with limited product management resources, taking ownership of discovery and scope definition # Tech Stack Ruby, Ruby on Rails, PostgreSQL / MySQL, Google Cloud Platform (Cloud Run, Cloud Build), Docker, GitHub Actions, RSpec, Rubocop # Skills - Product Engineering - Backend Development (Ruby on Rails)- Domain Modeling / Business Logic Design - API & Data Model Design - Incremental Delivery & Refactoring - Cloud-based System Operation (GCP)- Cross-functional Collaboration # Languages Japanese: Native English: Technical Reading & Writing