Software Engineer II

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 II
Overview
Mastercard's Fraud Products team develops capabilities for the Decision Management Platform, which supports solutions designed to combat fraud and validate cardholder identity. This Java-based platform processes billions of transactions each month using a distributed, message-oriented architecture built for high performance and availability.
As a Software Engineer II, you will develop, test, deploy, and support applications and services within this platform. You will independently apply core software engineering skills in routine and moderately complex situations, partnering with technical leads and other team members when addressing unfamiliar or highly complex challenges.
What You'll Do
Software Development• Design, build, test, deploy, and maintain Java-based applications and services.• Translate business and technical requirements into maintainable software solutions.• Apply data structures and programming concepts to support efficient system performance.• Integrate vendor and open-source technologies into existing systems.• Contribute to Agile discovery, planning, development, and delivery activities.
Design & Architecture• Develop software designs that address functional, performance, security, and operational requirements.• Apply established architectural patterns and standards when building distributed applications.• Partner with technical leads to understand system interactions, dependencies, and design decisions.• Support high-performance, highly available transaction-processing solutions.
Quality & Secure Engineering• Create and maintain unit, functional, and integration tests.• Apply secure coding practices throughout the software development lifecycle.• Participate in code reviews to improve readability, maintainability, and adherence to engineering standards.• Identify and resolve defects before they affect production systems.
Performance & Operational Excellence• Analyze and optimize application performance, scalability, and reliability.• Troubleshoot technical issues and support the resolution of production incidents and problem tickets.• Contribute to monitoring, observability, alerting, and operational readiness.• Develop an understanding of application runtime behavior, dependencies, infrastructure, and support requirements.
Collaboration• Partner with engineers, technical leads, Product, Architecture, and other cross-functional teams.• Communicate effectively within a globally distributed environment.• Share technical knowledge and contribute to continuous improvement.• Demonstrate ownership, initiative, and accountability for assigned work.
Required Qualifications• Bachelor's degree in Computer Science, Engineering, Information Technology, Information Systems, or a related field, or equivalent practical experience.• Software development experience using Core Java, including multithreading.• Knowledge of Java/J2EE, Spring Framework, and Spring Boot.• Experience writing unit, functional, and integration tests.• Understanding of software design principles, architectural patterns, and distributed systems.• Ability to apply secure coding practices and participate in code reviews.• Knowledge of data structures and their application to software development.• Experience troubleshooting applications and supporting production issues.• Familiarity with performance testing, monitoring, analysis, or system optimization.• Understanding of observability and operational support practices.• Experience with Oracle, PL/SQL, and advanced SQL scripting.• Knowledge of Agile development practices and test-driven development.• Ability to work independently on routine and moderately complex assignments, seeking guidance when addressing unfamiliar or highly complex situations.• Strong communication, collaboration, organizational, and problem-solving skills.
Preferred Qualifications• Experience with high-performance, high-availability transaction-processing systems.• Knowledge of distributed computing technologies such as GemFire, Apache Spark, Redis, Hazelcast, GridGain, or similar platforms.• Familiarity with messaging technologies such as MQ and JMS.• Experience using Splunk to create dashboards, alerts, or monitors.• Knowledge of Linux and shell scripting.• Experience integrating vendor and open-source products into enterprise systems.• Familiarity with development environments such as IntelliJ IDEA or JBoss Developer Studio.• Experience within payments, fraud prevention, financial services, or another regulated industry.
Success Measures
A successful Software Engineer II will:• Independently deliver assigned software features from development through production support.• Produce maintainable code that follows established design, testing, and security standards.• Apply software architecture and data structure concepts to routine and moderately complex solutions.• Effectively troubleshoot defects, incidents, and performance concerns.• Strengthen application reliability through testing, monitoring, and operational readiness.• Participate constructively in code reviews and technical discussions.• Demonstrate growing ownership and consistency across the software development lifecycle.
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 01/11/2027. If the fill date has passed, Mastercard intends to fill this position as soon as possible.
Pay Ranges
O'Fallon, Missouri: $92,000 - $147,000 USD