We are seeking a skilled and driven Full-Stack Engineer to lead the development and operation of our high-stakes card payment platform. This system is the engine behind the Invoice Card Pay feature across our flagship products, including Money Forward Invoice Card Pay and Money Forward Kakebarai.

This is a mission-critical role where you will ensure the reliability and scalability of B2B payment solutions while collaborating with cross-functional teams in a modern, cloud-native environment.

Core Responsibilities :

- Lead the end-to-end development, operation, and continuous maintenance of the Business Payment Solution Provider (BPSP) platform.

- Architect and develop robust card payment systems utilizing GMO Payment Gateway (GMOPG) as the primary Payment Service Provider.

- Act as a key technical liaison between the Invoice Card Pay (ICP) team and the Cloud Transfer/Payment (CT) team in MFVn.

- You will also periodically sync with the Invoice (IV) team to ensure product alignment

- Monitor and optimize payment flows to ensure high availability and security for financial transactions.

Technical Requirements :

- Proven professional experience developing and scaling web applications using Ruby on Rails.

- Solid experience with modern frontend frameworks and a deep understanding of the client-side lifecycle.

Our Tech Stack :

- Backend : Ruby on Rails, GraphQL.

- Frontend : TypeScript, Next.js.

- Infrastructure : Kubernetes (k8s) Service Platform, MySQL 8.0 (AWS Aurora MySQL 3).

Preferred Skills & Experience :

- Practical experience designing and consuming GraphQL APIs.

- Hands-on experience building performant, SEO-friendly, or internal dashboard interfaces with Next.js.

- FinTech Domain Knowledge : Prior experience specifically developing card payment functionality or working with payment gateways is a significant advantage.

- Database Management : Familiarity with Aurora MySQL optimization and schema design.