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 Engineer
About the Role
The Mastercard Digital Enablement Services (MDES) team's mission is to make payments fast, easy, and secure. That's why we've developed technology that enables mobile payments (Apple Pay, Google Pay, Samsung Pay, Garmin Pay, etc.) with secure, tokenized remote commerce payments. We've experienced incredible success and growth, with billions of transactions being processed each year.
Our new focus is to scale MDES further and deliver the best possible customer experience. We're making our services faster, more reliable, and more scalable whilst meeting emerging on-soil regulations and increasing demand across the globe. This is an opportunity to work on software that operates on a global scale, where speed, reliability, and resilience matter every day. As a Senior Software Engineer, you will collaborate with engineers and product partners to design, build, test, and enhance solutions that support the movement of transactions around the world.
Role
As a Senior Software Engineer, you will:
Software Engineering & Development
• Design, build, test, deploy, and maintain software components, automation frameworks, and validation tools • Apply strong knowledge of data structures, algorithms, and efficient coding practices in building scalable solutions • Contribute to end-to-end software development lifecycle, including design, development, testing, deployment, and monitoring
Architecture & Design
• Participate in defining software architecture and design patterns to ensure scalability, reliability, and maintainability • Ensure systems are designed for testability, observability, performance, and operational readiness • Provide input into microservices and cloud migration strategies
Quality Engineering & Testing
• Develop and implement test automation frameworks and CI/CD integration pipelines (e.g., Jenkins, XLR) • Design comprehensive test strategies and plans, including performance, reliability, and production simulation testing • Ensure high code quality and coverage using tools such as Sonar or Clover
Security & Compliance
• Apply and promote secure coding practices, including code analysis, vulnerability detection, and mitigation strategies • Integrate security testing into CI/CD pipelines
Code Quality & Reviews
• Conduct and lead code reviews, ensuring adherence to coding standards, security practices, and maintainability • Act as a technical reviewer for system designs, test strategies, and implementation approaches
Operability & Performance
• Ensure systems are observable, monitorable, and resilient across environments • Perform performance engineering, including load testing, tuning, and bottleneck analysis • Troubleshoot complex production issues and ensure rapid resolution
Collaboration & Leadership
• Partner with developers, architects, and product teams to drive engineering best practices • Mentor junior engineers and contribute to knowledge sharing across teams • Evaluate and recommend tools, technologies, and frameworks for continuous improvement
All About You
• Demonstrated experience developing microservices with JAVA and Spring Boot, required • Proven skills working with relational SQL database, preferably PostgreSQL and Oracle SQL • Advanced understanding of cloud native architecture, PCF, and AWS • Clear proficiency with engineering principles used in building and running mission critical software capabilities (security, scalability, resiliency, customer experience, testing, operability, simplification) • Apply tools (e.g., Sonar, Zally, Checkmarx) and techniques to scan and measure code quality and anti-patterns as part of development activity • Ability to perform domain-driven design to architect and map software solutions to business contexts • Proficient in orchestrating release workflows and pipelines, and apply standardized pipelines via APIs to achieve CI and CD using industry standard tools (e.g., Jenkins, AWS, XL Release, others); • Ability to configure rules and build automation for code with vulnerability scanning and software composition analysis using standard tools (e.g., Sonar, JFrog, XRay, Veracode, others) • Manage builds and artifacts leveraging standard tools (e.g., Artifactory) to ensure error-free deployment of production code using canary and/or blue-green techniques • Ability to write clean, secure, testable code and contribute to unit, service, and integration testing. • Ability to work on relational data concepts, preferably with PostgreSQL databases. • Strong foundation in computer science fundamentals, including data structures, algorithms, and object-oriented design • Strong analytical and problem-solving skills, with the ability to debug issues and identify practical solutions. • Strong verbal and written communication skills and the ability to work effectively in a collaborative team environment. • Self-motivated, organized, and eager to learn, with a passion for continuous improvement and delivering results. • Strong hands-on experience in software engineering, including development and quality engineering • Proven experience working with: • Testing across platforms: Linux and web applications • Automation development and CI/CD integration and deployment (Jenkins / XLR/ GitHub Actions) and code coverage tools (Sonar, Clover) to ensure high code/ conditional coverage • Unit, functional, and integration testing • Performance testing and engineering • Strong knowledge and understanding of: • Software design principles (OOP, modularity, design patterns) • Software architecture concepts (microservices, distributed systems, scalability) • Data structures and algorithms • Experience with secure coding practices and application security principles (e.g., OWASP) • Ability to contribute to system design and architecture decisions; understanding use cases for advanced design patterns (e.g., service-to-worker, MVC, API Gateway, Intercepting Filter, Dependency Injection, Lazy Loading, all from the gang of four) to implement efficient code
Additional Preferred Qualifications
• Experience in cloud and microservices architecture or mainframe modernization • Experience designing systems for reliability, performance, and scalability • Domain knowledge in payments, tokenization and transaction processing systems • Experience designing, tuning, and debugging rules engines and decision logic used to detect and block fraudulent activity, • Strong root-cause analysis skills to trace why a decision was made across logs, data, and distributed services • Experience in applying machine learning and anomaly detection techniques • Experience with graph databases and graph analysis to uncover hidden relationships • Bachelor's or master's degree in computer science or equivalent experience is preferred degree in computer science or equivalent experience is preferred
Mastercard is a merit-based, inclusive, equal opportunity employer that considers applicants without regard to gender, gender identity, sexual orientation, race, ethnicity, disabled or veteran status, or any other characteristic protected by law. We hire the most qualified candidate for the role. In the US or Canada, if you require accommodations or assistance to complete the online application process or during the recruitment process, please contact [email protected] and identify the type of accommodation or assistance you are requesting. Do not include any medical or health information in this email. The Reasonable Accommodations team will respond to your email promptly.
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.

In line with Mastercard's total compensation philosophy and assuming that the job will be performed in the US, the successful candidate will be offered a competitive base salary and may be eligible for an annual bonus or commissions depending on the role. The base salary offered may vary depending on multiple factors, including but not limited to location, job-related knowledge, skills, and experience. Mastercard benefits for full time (and certain part time) employees generally include: insurance (including medical, prescription drug, dental, vision, disability, life insurance); flexible spending account and health savings account; paid leaves (including 16 weeks of new parent leave and up to 20 days of bereavement leave); 80 hours of Paid Sick and Safe Time, 25 days of vacation time and 5 personal days, pro-rated based on date of hire; 10 annual paid U.S. observed holidays; 401k with a best-in-class company match; deferred compensation for eligible roles; fitness reimbursement or on-site fitness facilities; eligibility for tuition reimbursement; and many more. Mastercard benefits for interns generally include: 56 hours of Paid Sick and Safe Time; jury duty leave; and on-site fitness facilities in some locations.
THIS POSTING RELECTS ONE OR MORE CURRENT VACANCIES ON OUR TEAM, AND MASTERCARD INTENDS TO FILL THIS POSITION BY 01/24/2027. If the fill date has passed, Mastercard intends to fill this position as soon as possible.
Pay Ranges
O'Fallon, Missouri: $115,000 - $184,000 USD