Java Software Engineer Jobs in O Fallon, MO (NOW HIRING)

Our Purpose

Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we're helping build asustainableeconomy where everyone can prosper. We support a wide range of digital payments choices, making transactionssecure, 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

Senior Software Engineer- RPPS PlatformWho is Mastercard?
Mastercard powers economies and empowers people in more than 200 countries and territories worldwide. Together with our customers, we are helping build a sustainable economy where everyone can prosper. Our technology, innovation, partnerships, and networks combine to deliver unique products and services that help people, businesses, and governments realize their greatest potential.
Overview
The Transfer Solutions organization is seeking a Senior Software Engineer to join the RPPS (Remote Payment and Presentment System) platform team. This team develops and supports critical software solutions that enable payment processing capabilities across Mastercard's ecosystem.
This role is ideal for an experienced full-stack engineer who enjoys building modern applications, designing scalable APIs, solving complex technical problems, and contributing to high-performing Agile engineering teams. The successful candidate will participate across the entire software development lifecycle, from solution design and architecture through development, testing, deployment, optimization, and production support.
The position requires strong expertise in Java, Spring Boot, API development, and modern front-end technologies, coupled with a passion for engineering excellence, technical leadership, and continuous improvement. Based on the intake discussion, the role supports the RPPS platform and currently utilizes Java, Spring Boot, Angular, APIs, and automation-focused development work.
Role
As a Senior Software Engineer, you will:
Design, develop, test, deploy, and maintain scalable software applications that support Mastercard's payment processing platforms.
Build and enhance full-stack solutions utilizing Java, Spring Boot, Angular, APIs, and modern software engineering frameworks.
Collaborate with Product, Architecture, Platform Engineering, and Operations teams to translate business requirements into scalable technical solutions.
Contribute to application and service architecture decisions that improve scalability, maintainability, resilience, and long-term platform evolution.
Design and develop RESTful APIs and service integrations supporting enterprise-scale transaction processing.
Participate in Agile development activities including backlog refinement, sprint planning, standups, retrospectives, and solution reviews. The intake notes indicate responsibilities around picking up stories, contributing to requirements, participating in standups, and retrospectives.
Develop automated unit, functional, and integration tests to ensure software quality, reliability, and maintainability.
Perform code reviews and provide constructive feedback to improve code quality, consistency, and adherence to engineering standards.
Troubleshoot and resolve complex technical issues across applications, APIs, databases, and production environments.
Analyze system behavior and optimize application performance, scalability, and reliability for business-critical workloads.
Implement secure coding practices and proactively address application security risks throughout the software development lifecycle.
Design systems with operational readiness in mind, incorporating monitoring, logging, alerting, and observability best practices.
Support production deployments, incident response, root cause analysis, and continuous service improvement activities.
Mentor and support other engineers by sharing technical knowledge and promoting engineering best practices.
Continuously evaluate emerging technologies, frameworks, and tools that improve software delivery and platform capabilities.
All About You
Required Qualifications
Strong experience developing enterprise applications using Java and Spring Boot.
Experience building and consuming REST APIs in distributed application environments. The intake discussion referenced API development as a core r responsibility.
Experience with modern front-end development technologies, including Angular or similar frameworks.
Strong understanding of software development principles, object-oriented design, and distributed application architectures.
Experience designing, implementing, and maintaining automated testing solutions including unit, functional, and integration testing.
Experience conducting code reviews and driving engineering quality improvements.
Strong troubleshooting and root cause analysis skills within complex application environments.
Demonstrated understanding of secure coding practices and application security principles.
Experience analyzing and optimizing system performance, scalability, and operational reliability.
Strong knowledge of data structures, algorithms, and software design patterns.
Excellent communication, collaboration, and problem-solving skills.
Preferred Qualifications
Experience working on payment processing, transaction processing, or financial technology platforms.
Experience with cloud-native architectures and containerized deployment models.
Experience implementing CI/CD pipelines and DevOps practices.
Familiarity with observability platforms, monitoring tools, and operational excellence practices.
Experience supporting highly available mission-critical systems.
Experience mentoring engineers and influencing technical decisions across teams.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 reasonable_accommodation@mastercard.com 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.

Pay Ranges

O'Fallon, Missouri: $115,000 - $184,000 USD