Lead Software Development Engineer in Test (Lead SDET)

Mastercard • O'fallon, MO

1d • Hybrid

About The Position

Mastercard’s Global Credit Card Authorization team is seeking a Lead Software Development Engineer in Test (Lead SDET) to drive quality engineering for one of the most critical transaction processing platforms in the world. This platform facilitates billions of transactions annually between issuers, acquirers, and service providers across the globe. In this role, you will combine deep technical expertise with leadership to define and scale testing strategies for complex, high-throughput systems. You will play a pivotal role in elevating engineering standards, strengthening production readiness, and embedding quality across the entire software development lifecycle. You will also mentor engineers and influence quality practices across teams. This is a hybrid role based in O’Fallon, MO, with an expectation of three days per week onsite.

Requirements

• Extensive experience as a Software Development Engineer in Test (SDET), Quality Engineer, or similar role in large-scale, high-availability systems.
• Strong proficiency in C/C++ with hands-on software development experience for test development and system validation.
• Experience designing and implementing automated test frameworks and scalable testing strategies.
• Proven ability to develop and execute functional, integration, and User Acceptance Testing (UAT) for complex systems.
• Ability to translate high-level design and architecture documents into detailed, actionable test plans.
• Strong understanding of software quality engineering practices, defect lifecycle management, and test coverage methodologies.
• Experience working in Linux/Unix environments.
• Proficiency in scripting languages, preferably shell scripting, for automation and test execution.
• Experience with CI/CD pipelines, automated testing tools, and modern DevOps practices.
• Strong experience using source control systems (Git preferred) in collaborative development environments.
• Deep understanding of distributed systems, high-throughput architectures, and performance considerations.
• Strong analytical and problem-solving skills with a focus on root cause analysis and defect prevention.
• Proven ability to lead testing efforts and influence quality strategy across teams or domains.
• Excellent communication and stakeholder management skills, with the ability to influence both technical and non-technical audiences.
• Bachelor’s degree in Computer Science, Engineering, Mathematics, or a related technical field (or equivalent practical experience)

Nice To Haves

• Experience mentoring or leading engineers is strongly preferred.

Responsibilities

• Lead development of complex system components in C and design corresponding unit tests in C++ using Google Test.
• Translate high-level design documents and system architecture into detailed, actionable test plans and validation strategies.
• Design, implement, and execute functional, integration, and User Acceptance Testing (UAT) strategies across the platform.
• Own end-to-end quality outcomes for key authorization services, ensuring high performance, resilience, and reliability.
• Review system traces, logs, and runtime behavior to ensure comprehensive test coverage and system validation.
• Lead root cause analysis for complex issues, driving resolution and preventing recurrence.
• Identify, prioritize, and remove testing blockers to ensure timely and high-quality release delivery.
• Ensure production readiness by proactively identifying risks, validating fixes, and resolving defects prior to deployment.
• Drive continuous improvement in test automation, quality engineering practices, and CI/CD integration.
• Collaborate across engineering, product, and operations teams in a fast-paced, global environment to align on quality standards.
• Guide and mentor SDETs and QA engineers, fostering a culture of accountability, ownership, and continuous improvement.
• Champion high-confidence releases by embedding quality early in the development lifecycle and improving platform-wide testing strategies.

Benefits

• insurance (including medical, prescription drug, dental, vision, disability, 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

What This Job Offers

• Job Type: Full-time
• Career Level: Senior