Senior Software Engineer

Mastercard•O'fallon, MO

14d•$115,000 - $184,000

About The Position

As a Senior Software Engineer on Mastercard’s Core Payments, Network Solutions team, you will develop software for payment and transaction-processing systems. You will combine software development and quality engineering to deliver secure, scalable, and reliable applications and services. You will design, build, test, deploy, and maintain software components, automation frameworks, and validation tools. In collaboration with engineers, architects, and product teams, you will contribute to technical decisions, strengthen operational readiness, review code, and mentor junior engineers. The role spans the software development lifecycle, including deployment, monitoring, performance improvement, troubleshooting, and operational support. The position also involves developing automated validation for payment workflows, applying secure engineering practices, and contributing to architecture and cloud migration strategies. A successful engineer will deliver maintainable, well-tested software and help improve performance, reliability, observability, and team capabilities.

Requirements

Strong practical experience in software engineering, including development and quality engineering.
Demonstrated proficiency developing microservices with Java and Spring Boot.
Proficiency with relational databases and SQL.
Advanced understanding of cloud-native architecture, PCF, and AWS.
Experience deploying and managing containerized applications using Kubernetes.
Understanding of event-driven design and its application to distributed systems.
Ability to use Splunk for log analysis, monitoring, and troubleshooting.
Strong understanding of object-oriented programming, modularity, design patterns, distributed systems, data structures, and algorithms.
Ability to apply domain-driven design and contribute to system-design and architecture decisions, selecting appropriate patterns such as MVC, API Gateway, Intercepting Filter, Dependency Injection, Lazy Loading, and service-to-worker.
Proficiency applying security, scalability, resilience, customer experience, testing, operability, and simplification principles to mission-critical software.
Experience with unit, functional, and integration testing, including testing Linux and web applications.
Proficiency in test automation, CI/CD integration and deployment, and code-coverage measurement using tools such as Jenkins, XLR, GitHub Actions, Sonar, and Clover.
Experience with performance testing and engineering.
Ability to scan and assess code quality and anti-patterns using tools such as Sonar, Zally, and Checkmarx.
Experience applying secure coding and application-security principles, including OWASP, and configuring vulnerability scanning and software composition analysis using tools such as Sonar, JFrog Xray, and Veracode.
Ability to orchestrate release workflows and standardized pipelines through APIs using tools such as Jenkins, AWS, and XL Release.
Experience managing builds and artifacts using Artifactory and deploying production code using canary or blue-green techniques.
Strong analytical, troubleshooting, and problem-solving skills.
Clear verbal and written communication and effective collaboration across teams.

Nice To Haves

Knowledge of payment networks and transaction-processing systems.
Experience with PostgreSQL and Oracle SQL.
Experience delivering cloud and microservices architectures or mainframe modernization.
Experience designing systems for reliability, performance, and scalability.
Bachelor’s or master’s degree in Computer Science, or equivalent experience.

Responsibilities

Design, build, test, deploy, and maintain software components, automation frameworks, and validation tools for payment-processing applications and services.
Use data structures, algorithms, and efficient coding practices to develop scalable solutions.
Contribute across the software development lifecycle, including deployment and monitoring.
Translate business requirements into maintainable solutions using domain-driven design and established design patterns.
Contribute to architecture and system-design decisions that support scalability, reliability, testability, observability, and performance.
Provide input into microservices and cloud migration strategies.
Develop and maintain unit, functional, and integration tests across applications and services.
Build test automation frameworks and integrate validation into CI/CD pipelines.
Design test strategies covering payment workflows, service interactions, performance, reliability, and production simulation.
Measure code quality and coverage, and apply secure coding practices, vulnerability detection, and mitigation.
Conduct and lead code reviews; review system designs, test strategies, and implementation approaches.
Improve performance and scalability through load testing, tuning, and bottleneck analysis.
Build observability, monitoring, resilience, and operational readiness into solutions across environments.
Troubleshoot complex production issues, identify root causes, and support timely resolution.
Partner with engineering, architecture, and product teams to deliver solutions and strengthen engineering practices.
Mentor junior engineers and share technical knowledge across teams.
Evaluate and recommend tools, technologies, and frameworks for continuous improvement.
Orchestrate release workflows and standardized pipelines through APIs, manage builds and artifacts, and deploy production code using canary or blue-green techniques.

Benefits

Insurance, including medical, prescription drug, dental, vision, disability, and 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, prorated based on date of hire.
10 annual paid U.S. observed holidays.
401(k) with a company match.
Deferred compensation for eligible roles.
Fitness reimbursement or on-site fitness facilities.
Eligibility for tuition reimbursement.