Software Engineer II

Join Mastercard in O'Fallon, MO (onsite) and help build and operate the software that supports critical business capabilities. In this Software Engineer II role, you’ll design, develop, test, deploy, and support applications and services with an emphasis on security, scalability, resiliency, and performance. You’ll collaborate closely with engineers, product partners, and stakeholders while deepening your technical expertise across the end-to-end architecture and systems that power mission-critical work.

What You’ll Do

• Participate in team prioritization discussions with Product and Business stakeholders to understand requirements and delivery objectives.
• Estimate and deliver assigned work across the full lifecycle, including design, development, testing, deployment, configuration, and documentation.
• Contribute to code, design, and process discussions, helping evaluate trade-offs and arrive at practical solutions.
• Support sprint planning, backlog refinement, demos, and acceptance discussions with Product Owners and stakeholders.
• Build understanding of end-to-end technical architecture, business domain, and system dependencies for supported applications.
• Design, develop, test, and maintain software applications and services that meet security, scalability, resiliency, and performance requirements.
• Participate in code reviews and provide constructive feedback to maintain code quality and engineering standards.
• Apply engineering best practices, technology standards, and established development frameworks.
• Troubleshoot application, system, and production issues, working with teammates to identify root causes and implement fixes.
• Contribute to CI/CD pipelines, deployment automation, and operational readiness activities.
• Support and guide new team members through knowledge sharing and collaboration.
• Identify process improvements to reduce inefficiencies and enhance team productivity.
• Share knowledge, reusable components, patterns, and best practices across teams, guilds, and engineering communities.

What You Bring

• Experience developing software applications using modern programming languages and development frameworks.
• Understanding of software design principles, software architecture, data structures, and algorithms, with the ability to build maintainable, scalable solutions.
• Experience applying secure coding practices and familiarity with OWASP, CWE, and SEI CERT.
• Knowledge of vulnerability management and experience using code quality and security scanning tools such as Sonar, Checkmarx, Veracode, Zally, or similar solutions.
• Core engineering knowledge for mission-critical applications, including security, reliability, scalability, performance, operability, testing, and customer experience.
• Experience designing and maintaining unit, functional, integration, and automated tests.
• Familiarity with test automation concepts, behavior-driven development (BDD), and test pyramid methodologies.
• Experience participating in code reviews and troubleshooting application and production issues within distributed systems.
• Ability to collaborate with engineering teams and business stakeholders to estimate requirements and prioritize work by business value.
• Understanding of domain-driven design concepts and applying business requirements to software solutions.
• Experience with CI/CD pipelines and release automation tools such as Jenkins, Azure DevOps, AWS pipelines, XL Release, or similar technologies.
• Familiarity with build, artifact, and dependency management tools such as Artifactory (Jfrog) or equivalent platforms.
• Experience supporting monitoring, observability, performance analysis, and operational health using industry-standard tools.
• Experience building and supporting highly available production systems.
• Cryptography, encryption technologies, or security-focused applications is preferred.
• Payment industry experience is preferred but not required.
• Bachelor’s degree in Computer Science, Software Engineering, Information Technology, or a related field, or equivalent practical experience.

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, 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

Security Responsibilities

• 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.
• Complete all periodic mandatory security trainings in accordance with Mastercard’s guidelines.

Pay Range: O'Fallon, Missouri: $92,000 - $147,000 USD per year.