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

Overview
As a Senior Software Engineer in Mastercard’s Core Payments, Network Solutions team, you will develop software supporting payment and transaction-processing systems. You will combine software development and quality engineering to deliver secure, scalable, reliable applications and services.

You will design, build, test, deploy, and maintain software components, automation frameworks, and validation tools. Working with engineers, architects, and product teams, you will contribute to technical decisions, strengthen operational readiness, review code, and mentor junior engineers.

What You’ll Do
Software Development
• Design, build, test, deploy, and maintain software components, automation frameworks, and validation tools for payment-processing applications and services.
• Apply data structures, algorithms, and efficient coding practices to deliver scalable solutions.
• Contribute across the software development lifecycle, including deployment and monitoring.

Design & Architecture
• Translate business requirements into maintainable solutions using domain-driven design and established design patterns.
• Contribute to architecture and system-design decisions supporting scalability, reliability, testability, observability, and performance.
• Provide input into microservices and cloud migration strategies.

Quality & Secure Engineering
• Develop and maintain unit, functional, and integration tests across applications and services.
• Build test automation frameworks and integrate validation into CI/CD pipelines using tools such as Jenkins and XL Release (XLR).
• Design test strategies covering payment workflows, service interactions, performance, reliability, and production simulation.
• Measure code quality and coverage using tools such as Sonar and Clover.
• Apply and promote secure coding practices, vulnerability detection, and mitigation; integrate security testing into delivery pipelines.
• Conduct and lead code reviews, and review system designs, test strategies, and implementation approaches.

Performance & Operational Excellence
• Improve system performance and scalability through load testing, tuning, and bottleneck analysis.
• Build observability, monitoring, resilience, and operational readiness into solutions across environments.
• Troubleshoot complex production issues, identify root causes, and support timely resolution.

Collaboration & Technical Leadership
• Partner with engineering, architecture, and product teams to deliver solutions and strengthen engineering practices.
• Mentor junior engineers and share technical knowledge across teams.
• Evaluate and recommend tools, technologies, and frameworks for continuous improvement.

Required Qualifications
• Strong practical experience in software engineering, including development and quality engineering.
• Demonstrated proficiency developing microservices with Java and Spring Boot.
• Proficiency with relational databases and SQL.
• Advanced understanding of cloud-native architecture, PCF, and AWS.
• Experience deploying and managing containerized applications using Kubernetes.
• Understanding of event-driven design and its application to distributed systems.
• Ability to use Splunk for log analysis, monitoring, and troubleshooting.
• Strong understanding of object-oriented programming, modularity, design patterns, distributed systems, data structures, and algorithms.
• Ability to apply domain-driven design and contribute to system-design and architecture decisions, selecting appropriate patterns such as MVC, API Gateway, Intercepting Filter, Dependency Injection, Lazy Loading, and service-to-worker.
• Proficiency applying security, scalability, resilience, customer experience, testing, operability, and simplification principles to mission-critical software.
• Experience with unit, functional, and integration testing, including testing Linux and web applications.
• Proficiency in test automation, CI/CD integration and deployment, and code-coverage measurement using tools such as Jenkins, XLR, GitHub Actions, Sonar, and Clover.
• Experience with performance testing and engineering.
• Ability to scan and assess code quality and anti-patterns using tools such as Sonar, Zally, and Checkmarx.
• Experience applying secure coding and application-security principles, including OWASP, and configuring vulnerability scanning and software composition analysis using tools such as Sonar, JFrog Xray, and Veracode.
• Ability to orchestrate release workflows and standardized pipelines through APIs using tools such as Jenkins, AWS, and XL Release.
• Experience managing builds and artifacts using tools such as Artifactory and deploying production code using canary or blue-green techniques.
• Strong analytical, troubleshooting, and problem-solving skills.
• Clear verbal and written communication and effective collaboration across teams.

Preferred Qualifications
• Knowledge of payment networks and transaction-processing systems.
• Experience with PostgreSQL and Oracle SQL.
• Experience delivering cloud and microservices architectures or mainframe modernization.
• Experience designing systems for reliability, performance, and scalability.
• Bachelor’s or master’s degree in Computer Science, or equivalent experience.

Success Measures (First 12 Months)
A successful Senior Software Engineer will:
• Deliver assigned software components and supporting automation through design, testing, deployment, and maintenance.
• Strengthen automated validation of payment workflows and service interactions.
• Produce secure, maintainable code supported by effective testing and code reviews.
• Contribute to improvements in performance, reliability, observability, and operational readiness.
• Resolve complex technical issues and contribute practical improvements that reduce recurrence.
• Support team capability through mentoring, technical reviews, and knowledge sharing.

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