Senior Software Engineer

Mastercard•O'fallon, MO

13d•$115,000 - $184,000•Onsite

About The Position

Mastercard is a global technology company in the payments industry, focused on powering an inclusive, digital economy that makes transactions safe, simple, smart, and accessible. Using secure data and networks, our innovations enable individuals, financial institutions, governments, and businesses worldwide to realize their greatest potential. Within Mastercard’s Builders Enablement Program (ONE Division), we are building a standardized, secure, cloud first software delivery ecosystem and delivering a world class developer experience. We are seeking a Senior Software Engineer to design, build, and enhance software applications and developer-facing experiences that empower engineers across Mastercard's software delivery ecosystem. This role requires deep expertise in software architecture, application development, user experience, and distributed systems, combined with full lifecycle ownership from design through production operations.

Requirements

Demonstrated experience designing and developing scalable software systems using object-oriented design principles, modern software architecture patterns, and cloud-native development practices.
Proficient experience in software development and system design, with demonstrated ownership of large-scale distributed systems
Proficient expertise in: Software Design & Software Architecture
Unit, Integration, and Functional Testing frameworks and strategies
Operability engineering (observability, monitoring, reliability)
Advanced hands-on experience with: Performance Engineering and system optimization
Secure coding practices and application security principles
Code reviews and engineering quality standards
Data Structures & Algorithms
Troubleshooting complex distributed systems
Advanced proficiency in modern programming languages (e.g., Java, C#) and frontend development using React and/or TypeScript
Experience designing extensible software architectures and integrating developer tools through APIs, plugins, and event-driven patterns.
Experience with plugin-based architectures and integrating DevOps tools
Proven ability to build data-driven user interfaces
Hands-on experience developing and deploying cloud-native software using AWS, Kubernetes, containerized architectures, and modern engineering practices.
Proficient experience with CI/CD pipelines and Infrastructure as Code (Terraform, CloudFormation)
Experience with observability platforms (e.g., Splunk or equivalent)
Excellent communication and technical leadership skills

Nice To Haves

Bachelor’s or Master’s degree in Computer Science, Engineering, or related field preferred

Responsibilities

Design, develop, test, and support scalable cloud-native applications and services
Build and maintain backend solutions using Java and Spring Boot
Develop and enhance modern user interfaces using React and TypeScript
Design and implement REST APIs and service integrations across the Developer Experience ecosystem
Build integrations with developer tools including Jenkins, GitHub, Bitbucket, SonarQube, Workday, and related engineering platforms
Contribute to internal developer portals using Backstage or similar frameworks
Help improve engineering productivity through automation, self-service capabilities, and platform standardization
Own delivery of robust, secure, and high-performance software across backend platforms and frontend applications (React, TypeScript)
Drive engineering excellence in coding standards, modular design, and maintainability
Design and develop software solutions that improve developer productivity and streamline software delivery workflows using Backstage or similar frameworks and extensible plugin-based architectures.
Build modern, data-driven user experiences that transform engineering and operational data into actionable insights for software development teams.
Define and implement comprehensive testing strategies, including: Unit testing, Integration testing, Functional/end-to-end testing
Embed automated testing within CI/CD pipelines to enforce quality gates and prevent regressions
Ensure systems meet correctness, reliability, and backward compatibility requirements at scale
Lead performance engineering initiatives, including system benchmarking, load testing, and capacity planning
Analyze application and service performance, optimize system responsiveness, and improve scalability across highly distributed software systems.
Ensure applications meet strict performance SLAs in high-volume, mission-critical environments
Enforce secure coding practices and integrate security into every phase of the SDLC
Design systems that meet enterprise security, regulatory, and compliance requirements
Partner with security teams to proactively identify and remediate vulnerabilities
Serve as a senior technical leader for complex software production issues, leveraging deep troubleshooting expertise across distributed applications, APIs, integrations, and user-facing systems.
Lead root cause analysis, incident resolution, and postmortem activities
Drive systemic improvements to prevent recurring issues and improve system reliability
Lead rigorous code reviews, ensuring adherence to best practices in design, performance, security, and maintainability
Mentor engineers and elevate team capability in software design, testing, debugging, and operational excellence
Provide hands-on guidance in solving high-complexity technical problems across system layers
Partner with product, platform, and business stakeholders to shape technical roadmaps and delivery priorities
Own and deliver cross-functional software engineering initiatives spanning frontend applications, backend services, APIs, integrations, and cloud-native architectures.
Contribute to the Software Engineering Guild by sharing reusable frameworks, patterns, and innovations

Benefits

insurance (including medical, prescription drug, dental, vision, disability, life insurance)
flexible spending account and health savings account
16 weeks of new parent leave
up to 20 days of bereavement leave
80 hours of Paid Sick and Safe Time
25 days of vacation time
5 personal days
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