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
Overview
At Mastercard Commercial Solutions, we empower businesses to succeed through innovative, trusted payment solutions that deliver seamless, digital-first experiences around the world.
We are building a global business-to-business (B2B) technology platform that helps businesses of all sizes streamline how they manage payments when buying or selling products and services.
The Mastercard Commercial Solutions team is looking for a Senior Software Engineer to advance our customer experience strategy through innovation and problem-solving. The ideal candidate is passionate about the customer journey and is highly motivated, intellectually curious, and analytical.
Role
You will work at our Mastercard technology location in O'Fallon, which provides a collaborative, state-of-the-art environment where technology teams can thrive within our Agile engineering culture. You will play a key role in transforming the B2B space by helping standardize, automate, and optimize digital payment efficiency for buyers and sellers.• Own software delivery activities at the application or software-component level, including design, development, testing, deployment, support, documentation, and configuration.• Develop full-stack solutions, including front-end applications, REST APIs, and backend services.• Translate business and technical requirements into scalable, secure, and maintainable software designs, defining appropriate components and system interactions.• Participate in Scrum ceremonies and contribute to continuous improvement using Agile methodologies.• Drive code, design, and process trade-off discussions within the team.• Promote the adoption of engineering principles, technology standards, and best practices.• Review code, testing, and automation produced by team members to ensure quality, security, standards compliance, and maintainability.• Develop a strong understanding of end-to-end technical architecture and system dependencies.• Evaluate application architecture and design decisions with consideration for scalability, performance, reliability, and long-term maintainability.• Mentor and guide new and less-experienced team members.• Develop and maintain unit, integration, functional, and regression tests.• Analyze and optimize application performance through testing, measurement, troubleshooting, and tuning.• Design and maintain applications for operational readiness by incorporating reliability, observability, monitoring, and effective production-support practices.• Troubleshoot production incidents and implement corrective and preventive actions.• Share and seek knowledge within the Guild and program to promote the reuse of patterns, libraries, and engineering practices.
All About You
Required Experience• Experience developing secure full-stack applications using backend and front-end technologies such as Java, JavaScript, Angular, and SQL.• Strong knowledge of Spring, Spring Data JPA, REST APIs, Kafka, and related frameworks.• Experience designing, implementing, and maintaining unit, service, integration, functional, and regression tests using tools such as JUnit, Mockito, and Jasmine.• Knowledge of application and design patterns used to implement APIs, event-driven services, batch services, and user-interface applications.• Strong understanding of data structures and their application in building efficient, reliable, and maintainable software.• Experience applying secure coding standards and vulnerability-management practices throughout the software development lifecycle.• Experience implementing API standards and cataloging practices to support service adoption, reuse, and commercialization.• Experience using tools such as Sonar, CxOne, Checkmarx, Black Duck, and Zally to evaluate code quality, security vulnerabilities, and anti-patterns.• Experience orchestrating release workflows and implementing standardized continuous integration and continuous delivery pipelines using tools such as Jenkins and XL Release.• Experience evaluating and improving application performance, scalability, and reliability using appropriate testing and tuning techniques.• Strong problem-solving and creative troubleshooting skills, with the ability to diagnose and resolve issues across applications and integrated systems.• Strong organizational skills and the ability to manage multiple priorities within business timelines.• Self-motivated and proactive, with a commitment to continuous improvement and delivering results.• Ability to thrive in a fast-paced, rapidly changing, and customer-focused environment.• Ability to promote full-stack engineering practices and end-to-end service ownership across teams.• Strong written and verbal communication skills.• Bachelor's degree in Computer Science, Software Engineering, or a related field.• Eight or more years of relevant software engineering or information technology experience.
Desirable Skills• Experience with monitoring and observability tools such as Splunk or Dynatrace.
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 12/27/2026.
Pay Ranges
O'Fallon, Missouri: $115,000 - $184,000 USD