Software Engineer I

Our Purpose
Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we're helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential.
Title and Summary
Software Engineer I
About the Role
Join Mastercard's Transaction Stream team in O'Fallon, Missouri, and help build the applications and services that power critical capabilities across the real-time payment network. This is an opportunity to work on software that operates on a global scale, where speed, reliability, and resilience matter every day. As a Software Engineer I, you will collaborate with engineers and product partners to build, test, and enhance solutions that support the movement of transactions around the world.
Role and Responsibilities
Develop, test, maintain, and support software applications and services with guidance from experienced engineers
Write clean, maintainable, reusable, and secure code following established engineering standards, software design principles, and best practices
Participate in software design activities by translating functional and non-functional requirements into scalable, maintainable, and secure software components and services
Contribute to the implementation of established software architecture patterns and system designs while gaining experience with scalability, reliability, security, and long-term maintainability considerations
Develop and maintain unit, functional, and integration tests to ensure software quality, reliability, and correct system behavior
Apply knowledge of data structures, algorithms, and software engineering fundamentals to develop efficient and scalable software solutions
Participate in code reviews and incorporate feedback to improve code quality, maintainability, and engineering practices
Contribute to APIs, microservices, distributed applications, and event-driven solutions.
Apply secure coding practices and security-by-design principles throughout the software development lifecycle
Collaborate with Product, QA, Architecture, Security, DevOps, and Operations teams to deliver software solutions that meet business and technical requirements
Support cloud-based applications and services while assisting with monitoring, troubleshooting, root cause analysis, and issue resolution
Assist in monitoring, analyzing, and optimizing application performance, scalability, and resource utilization to meet business and operational requirements
Contribute to CI/CD, automation, observability, reliability, performance, and operational excellence initiatives
Help implement operational readiness practices, including logging, monitoring, alerting, and system supportability considerations
Continuously learn and adopt modern software engineering technologies, tools, and practices
All About You
Bachelor's degree in computer science, engineering, information technology, or a related field, or equivalent practical experience in Software Development through a relevant internship, Co-Op, research, or professional business is preferred.
Strong understanding of programming fundamentals, data structures, algorithms, and object-oriented design concepts.
Knowledge of software design principles and the ability to develop maintainable, scalable, and reusable software solutions.
Understanding common architectural concepts and patterns such as layered architectures, microservices, event-driven systems, and distributed applications.
Working knowledge of Java, Golang, Kotlin, C#, or similar programming languages.
Familiarity with Spring Boot, Spring, Hibernate, or similar frameworks.
Exposure to JavaScript, Angular, or similar front-end technologies is a plus.
Understanding REST APIs, microservices, relational databases, SQL, and software testing practices.
Familiarity with unit testing frameworks and automated testing methodologies.
Familiarity with Git, CI/CD pipelines, cloud platforms, DevOps practices, and Agile software development methodologies.
Basic understanding of application performance, scalability, monitoring, and observability concepts.
Understanding troubleshooting methodologies, root cause analysis, and problem-solving techniques.
Basic understanding of secure coding principles, OWASP guidelines, and application security best practices.
Strong analytical thinking, problem-solving, communication, collaboration, and continuous learning skills.
Mastercard is a merit-based, inclusive, equal opportunity employer that considers applicants without regard to gender, gender identity, sexual orientation, race, ethnicity, disabled or veteran status, or any other characteristic protected by law. We hire the most qualified candidate for the role. In the US or Canada, if you require accommodations or assistance to complete the online application process or during the recruitment process, please contact [email protected] and identify the type of accommodation or assistance you are requesting. Do not include any medical or health information in this email. The Reasonable Accommodations team will respond to your email promptly.
Corporate Security Responsibility
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.

In line with Mastercard's total compensation philosophy and assuming that the job will be performed in the US, the successful candidate will be offered a competitive base salary and may be eligible for an annual bonus or commissions depending on the role. The base salary offered may vary depending on multiple factors, including but not limited to location, job-related knowledge, skills, and experience. Mastercard benefits for full time (and certain part time) employees generally include: 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; and many more. Mastercard benefits for interns generally include: 56 hours of Paid Sick and Safe Time; jury duty leave; and on-site fitness facilities in some locations.
THIS POSTING RELECTS ONE OR MORE CURRENT VACANCIES ON OUR TEAM, AND MASTERCARD INTENDS TO FILL THIS POSITION BY 01/05/2027. If the fill date has passed, Mastercard intends to fill this position as soon as possible.
Pay Ranges
O'Fallon, Missouri: $72,000 - $115,000 USD