Location: Madrid, Spain (Hybrid – 2 days per week onsite)

About the Role:
As a Full Stack Developer, you'll join a cross-functional development team building innovative global payment solutions used by thousands of businesses and millions of users in over 190 countries. The R&D team of nearly 500 professionals operates in SCRUM and focuses on delivering high-quality features with speed, using Microsoft and open-source technologies. This role requires working onsite at the client’s Madrid office two days per week.

Requirements:
We follow a 2 out of 3 approach regarding mandatory technical skills, alongside strong object-oriented programming knowledge:

  • Object-oriented programming (mandatory)
  • Two out of three:
    • C#
    • SQL (e.g., MSSQL, advanced queries, optimization)
    • Microservices & messaging (e.g., Distributed Transactions, Eventual Consistency, Communication Patterns)
  • 3+ years of experience for strong middle level or 5+ years for senior level
  • Experience with frontend technologies (React, TypeScript) is a plus
  • Strong problem-solving skills and ability to make risk assessments
  • Hands-on capabilities to troubleshoot critical issues and contribute to architectural decisions
  • Upper-intermediate English level or higher (good communication skills required)
  • Readiness to work onsite in Madrid (2 days per week)
  • Candidates requiring sponsorship cannot be considered
  • Java developers willing to transition to .NET are eligible

Responsibilities:

  • Collaborate closely with Development, Product, Design/UX, DevOps, and other teams
  • Work as part of an autonomous scrum team in an agile environment
  • Develop scalable, secure, and efficient backend services and APIs
  • Implement and maintain modern, responsive frontend applications (if applicable)
  • Perform database design, optimization, and maintenance
  • Migrate existing Angular (v.13) and older React (v.15/16) pages to the latest React version
  • Convert vanilla HTML pages to React
  • Ensure the maintainability, performance, and security of the applications
  • Troubleshoot, debug, and optimize existing applications

Tech Stack Split:

  • 70% Backend (C#, .NET, SQL, Microservices & Messaging)
  • 30% Frontend (React, TypeScript) – if applicable