Senior Software Development Engineer

Senior Software Development Engineer

Overview

The Senior Software Development Engineer is a senior individual contributor responsible for designing, developing, and supporting highly scalable distributed systems. This role combines deep technical expertise with mentorship responsibilities and ownership of critical software components from design through production support.

What You Will Do

• Design software solutions and contribute to software architecture decisions that support scalability, maintainability, and operational excellence.
• Translate complex product requirements into technical designs and implementation plans.
• Lead development of modular, extensible, high-performance applications.
• Design and implement comprehensive unit, functional, and integration testing strategies.
• Analyze, optimize, and improve application performance, scalability, and reliability.
• Apply secure coding practices and promote application security best practices.
• Lead and participate in code reviews, ensuring adherence to engineering standards.
• Design systems with observability, operability, and supportability as core principles.
• Research emerging frameworks and technologies and recommend adoption where appropriate.
• Mentor junior developers and support onboarding activities.
• Troubleshoot and resolve complex production issues using root cause analysis techniques.
• Support engineering excellence through continuous improvement, refactoring, and adherence to SOLID principles.

All About You

• Strong hands-on experience with Java, Spring Boot, Kafka, REST APIs, JPA, and distributed systems.
• Strong understanding of software design and software architecture principles.
• Experience building highly scalable and resilient systems.
• Experience implementing automated testing strategies and quality engineering practices.
• Strong knowledge of performance engineering and production optimization.
• Strong understanding of secure software development principles.
• Experience leading code reviews and mentoring engineers.
• Strong troubleshooting and analytical problem-solving skills.
• Experience with microservices, cloud-native applications, and CI/CD.
• Experience building AI-assisted applications, autonomous agents, or agentic workflows.
• Agile Scrum experience.

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 click.appcast.io 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