Senior Software Engineer - Integrations & API Connectivity

Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we're helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential.

Senior Software Engineer
- Integrations & API Connectivity Overview Mastercard  is a global technology company powering an inclusive, digital economy, enabling secure and seamless transactions across 210+ countries. This role sits within Mastercard's Open Finance Europe
- Connectivity team, responsible for building and operating scalable API integrations with financial institutions across Europe. As a Senior Software Engineer, you will be a key hands-on contributor responsible for designing, building, and operating secure, reliable backend services. You will work on complex engineering problems, contribute to system design decisions, and deliver high-quality solutions that operate at scale in production environments.

• Design, develop, test, and support scalable APIs and backend services
• Contribute to system design decisions with a focus on scalability, resilience, and performance
• Deliver high-quality, production-ready code across the full software development lifecycle
• Troubleshoot and resolve production issues, ensuring system stability and reliability
• Participate in code reviews and uphold engineering best practices and standards
• Implement effective testing strategies (unit, integration, end-to-end)
• Collaborate with cross-functional teams including Product, Architecture, Security, and SRE
• Improve observability, automation, and operational efficiency across services

• Backend: C#, .NET, Web APIs
• Cloud:
  Azure (App Services, Key Vault, Blob Storage), AWS (S3, Redis, Microservices)
• Data:
  PostgreSQL, Flyway
• Practices: CI/CD pipelines, observability, secure development
• Plus:
  Java / Spring Boot, AI-assisted tools (e.g., Git Hub Copilot)

• 3-5 years of professional software engineering experience
• Strong hands-on experience building cloud-based, distributed backend systems
• Solid expertise in API development, scalability, and production support
• Ability to solve complex technical problems with a structured, pragmatic approach
• Strong understanding of SDLC, testing practices, and secure coding principles
• Proven ability to own and deliver components/services independently
  
  Strong collaboration and communication skills

• Experience in payments, banking, or Open Banking (PSD2) environments
• Experience working with microservices architectures
• Familiarity with observability, monitoring, and incident response practices
• Exposure to AI-assisted development tools (e.g., Git Hub Copilot)

• Abide by Mastercard's security policies and practices;
• Ensure the confidentiality and integrity of the information being accessed;
• Report any suspected information security violation or breach, and
• Complete all periodic mandatory security trainings in accordance with Mastercard's guidelines.