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# Senior Software Engineer

- **Company:** Mastercard
- **Location:** O'Fallon, MO, United States
- **Experience:** Expert
- **Salary:** $115,000.0 - $184,000.0
- **Contract:** Permanent contract
- **Skills:** Java (Programming Language), Artificial Intelligence, Amazon Web Services, Automation of Tests, Microsoft Azure, Code Coverage, Software Quality, Code Review, Cyber Security, Data Structures, Identity and Access Management, Performance Tuning, Scrum Methodology, Software Architecture, Secure Coding, Software Engineering, Software Vulnerability Management, Data Logging, Spring Cloud, Spring-boot, Reliability of Systems, Event Driven Architecture, Containerization, Integration Tests, Kubernetes, Apache Kafka, Restful APIs, Docker, Microservices
- **Published:** June 6, 2026
- **Apply:** https://mastercard.wd1.myworkdayjobs.com/CorporateCareers/job/OFallon-Missouri/Senior-Software-Engineer_R-279539

## About the Role

*Experience building RESTful services using Java and Spring Boot
*Strong experience designing scalable systems using modern software design and architecture principles
*Experience with cloud platforms (AWS, Azure, or GCP) and containerization (Docker, Kubernetes)
*Proven ability to work independently on complex technical problems and support team outcomes
*Experience writing and maintaining unit, functional, and integration tests
*Strong understanding of performance engineering (analyzing and optimizing systems at scale)
*Expertise in secure coding practices and vulnerability management
*Experience leading and contributing to code reviews and engineering standards
*Strong troubleshooting and root cause analysis skills in complex environments
*Solid understanding of data structures and their impact on performance and scalability
*Experience building systems with strong operability, monitoring, and reliability practices
*Experience working in Agile/Scrum environments and collaborating across teams
*Strong communication and collaboration skills, with the ability to influence technical decisions
*Experience mentoring or supporting other engineers
*Bachelor's degree or equivalent experience

Nice to Have
*Knowledge of event-driven architectures (Kafka or similar)
*Experience in high-throughput or regulated environments (payments, banking, fintech)
*Exposure to AI/automation tools within software development workflows

## Description

As part of a fast-paced team building authentication and security solutions, you will help design and deliver secure, scalable, and high-performing software for Mastercard's Identity Solutions platform.

As a Senior Software Engineer, you'll take ownership of complex technical work, contribute to design and architecture decisions, and support the team in delivering reliable, production-ready systems. You'll collaborate closely with product, security, and platform teams to build solutions that meet both business and technical needs.

Role
*Design, build, test, deploy, and maintain scalable, cloud-native applications and microservices
*Develop REST APIs using Java and Spring Boot, focusing on performance, scalability, and reliability
*Translate requirements into well-structured designs and architecture, ensuring maintainability and security
*Lead and contribute to system design discussions, aligning with architectural standards and best practices
*Write and maintain unit, functional, and integration tests to ensure quality and reliability
*Drive improvements in test automation, code coverage, and system reliability
*Analyze and optimize system performance, scalability, and efficiency
*Apply secure coding practices and lead vulnerability remediation efforts (CVE remediation, upgrade automation)
*Perform and lead code reviews to improve code quality, maintainability, and adherence to standards
*Troubleshoot and resolve complex production issues using structured problem-solving and root cause analysis
*Ensure systems are built with strong operability (monitoring, logging, reliability, support readiness)
*Contribute to CI/CD pipelines and engineering practices that improve delivery speed and quality
*Collaborate across teams (product, QA, platform) to deliver high-quality solutions
*Mentor junior engineers and support knowledge sharing across the team
*Contribute to a culture of continuous improvement, accountability, and collaboration, 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., 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.


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