Software Engineer II

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 Software Engineer II Overview Join Mastercard’s Core Payments, Network Solutions team to develop software that supports secure, reliable, and scalable payment-processing capabilities. This role combines software development, quality engineering, and operational readiness to help deliver dependable solutions across the payments ecosystem. As a Software Engineer II, you will design, build, test, deploy, and maintain software components, automation frameworks, and validation tools supporting payment applications and services. You will apply strong engineering fundamentals to system interactions, transaction-processing workflows, performance, and resilience. You will independently execute routine and moderately complex assignments, with occasional guidance on unfamiliar or highly complex work. What You'll Do Software Development • Design, build, test, deploy, and maintain software components, automation frameworks, and validation tools supporting Core Payments, Network Solutions applications and services. • Develop microservices using Java and Spring Boot and work with relational SQL databases. • Apply data structures, algorithms, and efficient coding practices to build scalable solutions. • Contribute across the software development lifecycle, including deployment, monitoring, and ongoing maintenance. Design & Architecture • Participate in software design and architecture discussions, applying established patterns to support scalability, reliability, and maintainability. • Apply domain-driven design principles to translate payment-processing requirements and service interactions into maintainable software solutions. • Design components for testability, observability, performance, and operational readiness. • Contribute to microservices and cloud migration approaches. Quality & Secure Engineering • Develop and maintain unit, functional, and integration tests, automation frameworks, and CI/CD testing integrations. • Contribute to test strategies and plans covering transaction-processing workflows, service integrations, performance, reliability, and production simulation. • Use code analysis and coverage tools to identify quality issues, anti-patterns, and testing gaps. • Apply secure coding standards and integrate security testing, vulnerability scanning, and software composition analysis into delivery pipelines. • Participate in peer code reviews and technical reviews of designs, test strategies, and implementation approaches. Performance & Operational Excellence • Analyze and improve transaction-processing performance, response times, and scalability through load testing, tuning, and bottleneck analysis. • Support observability, monitoring, resilience, and operational readiness across environments. • Diagnose production issues, identify root causes, and implement practical solutions, seeking guidance on unfamiliar or highly complex scenarios. • Manage release workflows, builds, and artifacts through standardized CI/CD pipelines, including canary or blue-green deployment techniques. Collaboration • Partner with engineering, architecture, product, and operational stakeholders to deliver payment solutions and strengthen engineering practices. • Share knowledge and support colleagues through collaborative problem-solving and peer feedback. • Evaluate tools, technologies, and frameworks and recommend opportunities for continuous improvement. • Communicate clearly and work effectively within a collaborative team environment. Required Qualifications • Demonstrated software development and quality engineering experience, including building microservices with Java and Spring Boot. • Proficiency with relational data concepts and SQL databases, preferably PostgreSQL and Oracle SQL. • Strong understanding of cloud-native architecture, including AWS, PCF, and Kubernetes, and microservices, distributed-systems, and event-driven design concepts. • Knowledge of object-oriented programming, modularity, software design patterns, data structures, and algorithms. • Ability to apply domain-driven design and contribute to system design decisions using appropriate patterns, such as MVC, API Gateway, Dependency Injection, Lazy Loading, service-to-worker, and Intercepting Filter. • Understanding of mission-critical engineering principles relevant to payment applications, including security, scalability, resilience, customer experience, testing, operability, and simplification. • Ability to develop and execute unit, functional, integration, and performance tests across Linux and web applications. • Experience developing test automation and integrating testing, code coverage, and deployment into CI/CD pipelines using tools such as Jenkins, XL Release (XLR), GitHub Actions, Sonar, and Clover. • Knowledge of secure coding and application security principles, such as OWASP, and participation in peer code reviews. • Ability to configure code-quality checks, vulnerability scanning, and software composition analysis using tools such as Sonar, Zally, Checkmarx, JFrog Xray, and Veracode. • Ability to orchestrate release workflows, use standardized pipelines through APIs, and manage builds and artifacts with tools such as Artifactory, including canary or blue-green deployments. • Strong analytical, debugging, and problem-solving skills, including performance analysis and production troubleshooting using Splunk. • Clear verbal and written communication and effective collaboration with engineering and product partners. Preferred Qualifications • Experience in cloud and microservices architecture or mainframe modernization. • Experience designing systems for reliability, performance, and scalability. • Domain knowledge of payment networks, transaction-processing workflows, or integrations between payment systems. • Bachelor’s or master’s degree in Computer Science, or equivalent practical experience. Success Measures (First 12 Months) • Deliver assigned Core Payments, Network Solutions software components from design through testing, deployment, and maintenance. • Produce secure, maintainable code supported by peer reviews and unit, functional, and integration tests. • Strengthen test automation, code coverage, and CI/CD release processes. • Contribute to measurable improvements in payment-application performance, scalability, reliability, and observability. • Resolve application and production issues through systematic troubleshooting and root-cause analysis. • Collaborate effectively with engineering, architecture, and product partners and contribute to 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 View email address on joinrs.com 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 01/26/2027. If the fill date has passed, Mastercard intends to fill this position as soon as possible. Pay Ranges O'Fallon, Missouri: $92,000 - $147,000 USD