Senior Software Engineer
Summary
Senior Software Engineer at Mastercard designing, developing, and maintaining scalable applications for MDES platform enhancements. Day-to-day work centers on Java, REST APIs, CI/CD-integrated test automation (Rest Assured/Karate/Selenium), secure coding, and performance/observability for distributed payment systems.
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 EngineerOverviewWe are seeking a Senior Software Engineer to design, develop, and maintain scalable software solutions supporting MDES initiatives and platform enhancements. This role combines strong software engineering fundamentals with automation and quality engineering practices to deliver secure, reliable, and high-performing applications. Based on the Senior Software Engineer skills matrix, the role emphasizes Software Development, Software Design, Software Architecture, Secure Coding, Code Review, Performance Engineering, Operability Engineering, Troubleshooting, and Testing.
Key Responsibilities
• Design, develop, test, deploy, and support scalable software applications and services.
• Translate business requirements into secure, maintainable, and efficient technical solutions.
• Contribute to software architecture, design reviews, and technical decision-making.
• Participate in code reviews to improve quality, security, and maintainability.
• Build and enhance APIs, services, and reusable software components.
• Develop and maintain automated tests covering unit, functional, integration, API, and end-to-end scenarios.
• Integrate automated testing and quality controls into CI/CD pipelines.
• Analyze and resolve complex application, integration, and production issues.
• Improve system reliability through monitoring, observability, performance optimization, and operational readiness.
• Mentor engineers and promote engineering best practices across the team.
Required Skills
• Strong Java software development experience.
• Knowledge of software design, software architecture, data structures, and algorithms.
• Experience developing REST APIs and distributed applications.
• Experience with secure coding practices and code review processes.
• Strong troubleshooting and root cause analysis skills.
• Experience with unit, functional, and integration testing.
• Experience building automation using tools such as Rest Assured, Karate, Selenium, or similar frameworks.
• Understanding of CI/CD, DevOps practices, and cloud-native architectures.
• Experience with SQL and data validation.
• Knowledge of performance engineering, operability engineering, monitoring, and observability concepts. [
Preferred Experience
• Payments industry experience.
• MDES, DTS, TDS, Transaction Stream, Core Processing, or Tokenization experience.
• Experience developing automation frameworks and test infrastructure.
• Experience with performance, resiliency, and large-scale distributed systems.
Success Measures
• Delivery of secure, scalable, and maintainable software solutions.
• Increased automation coverage and engineering efficiency.
• High-quality releases with minimal defect leakage.
• Improved system reliability, performance, and operational readiness.
• Strong technical leadership and mentoring impact.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.
Pay Ranges
O'Fallon, Missouri: $115,000 - $184,000 USD