Senior Full-Stack Engineer - C# & React

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 Full-Stack Engineer - C# & React
Senior Full-Stack 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 payment 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 Full-Stack Engineer - Open Finance
Location: Copenhagen, Gdańsk or Dublin
Overview
As a Senior Full-Stack Engineer, you will design, build, and deliver cutting-edge Open Finance solutions that power Mastercard's next generation of payment and data products. You'll work across the entire technology stack - from highly available backend services to engaging front-end experiences - partnering closely with designers, product managers, and architects to bring ideas to life.
You will work with Connect, the frontend component of our Open Banking Payment and Data applications and help drive creative solutions in pursuit of a world beyond cash. As such, this role requires a blend of backend engineering expertise (.NET / Java), frontend development skills (React), and the ability to collaborate across disciplines to deliver secure, scalable, and accessible software that meets the highest Mastercard standards.
Responsibilities
Plan, design, and develop full-stack solutions that meet business requirements while adhering to Mastercard's standards, processes, and best practices.
Collaborate with UI/UX designers to implement responsive, accessible user interfaces with React.
Ensure front-end applications meet WCAG accessibility guidelines, deliver great performance, and are optimised for multiple devices.
Build and maintain scalable backend services and APIs, integrating with Mastercard's Open Finance ecosystem.
Ensure high code quality with unit/integration testing, peer reviews, and continuous integration.
Contribute to the full software development life cycle, from requirements gathering to release and ongoing support.
Troubleshoot, debug, and resolve production issues, ensuring service reliability and performance.
Mentor junior engineers and promote knowledge sharing across the team.
Partner with product owners and stakeholders to prioritise features, communicate progress, and manage trade-offs.
Stay current with industry trends, frameworks, and best practices in both frontend and backend technologies.
All About You
5+ years of software engineering experience, with proven expertise across backend and frontend development.
Strong skills in .NET, plus proficiency in React.
Skills in Java would be beneficial but not essential.
Experience working with RESTful APIs, microservices, and cloud environments (AWS, GCP, or Azure).
Solid understanding of UI/UX principles, responsive design, and accessibility standards.
Experience collaborating with designers and product teams to bring user-centric solutions to market.
Knowledge of modern software engineering practices: CI/CD, automated testing, code reviews, Agile/Scrum.
Excellent communication and stakeholder management skills - able to translate technical needs to business language and vice versa.
Accountable, detail-oriented, proactive, and able to work independently in a fast-paced environment.
Bonus: Experience with Open Finance, payments, or regulated financial services.
Corporate Security Responsibility
All activities involving access to Mastercard assets, information, and networks come 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.
Mastercard is an inclusive equal opportunity employer that considers applicants without regard to gender, gender identity, sexual orientation, race, ethnicity, disability, veteran status, or any other characteristic protected by law.
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.