Senior Software Engineer - Backend & API Development

Senior Software Engineer

Our Purpose

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.

Title and Summary

Senior Software EngineerSenior Software Engineer — EU 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.

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What You’ll Do

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

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Technology Stack

Backend: C#, .NET, Web APIs

Cloud: Azure (App Services, KeyVault, 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., GitHub Copilot)

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What You Bring

Required

5–8 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

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Preferred

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., GitHub Copilot)

Corporate Security Responsibility

All activities involving access to Mastercard assets, information, and networks comes with an inherent risk to the organization and, therefore, it is expected that every person working for, or on behalf of, Mastercard is responsible for information security and must:

• 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.

Experience Level

Senior Level