# Senior Software Engineer

**Company**: Mastercard
**Location**: O'Fallon, Missouri
**Experience**: senior
**Job type**: full-time
**Salary**: $115,000 - $184,000 USD
**Category**: Engineering
**Industry**: Finance

**Apply**: https://mastercard.wd1.myworkdayjobs.com/en-US/CorporateCareers/job/OFallon-Missouri/Senior-Software-Engineer_R-282821?utm_source=yubhub.co&utm_medium=jobs_feed&utm_campaign=apply
**Canonical**: https://yubhub.co/jobs/job_2306615a-cd7

## Description

Join Mastercard's Transaction Stream team in O'Fallon, MO, and help build applications and services that power critical capabilities across the real-time payment network.

As a Senior Software Engineer, you will collaborate with engineers and product partners to design, build, test, and enhance solutions that support the movement of transactions around the world.

**Responsibilities**

- Design, develop, and maintain scalable test frameworks and automation solutions aligned with enterprise architecture standards

- Apply software design principles and architectural patterns to create maintainable and extensible testing and validation systems

- Contribute to system architecture discussions, ensuring solutions are testable, observable, secure, and performant

- Translate business and system requirements into well-designed technical solutions, test strategies, and validation models

- Ensure secure coding practices are embedded in development and testing processes, proactively identifying vulnerabilities and risks

- Develop and execute testing strategies across all levels: unit, functional, integration, system, and performance testing

- Leverage data structures and algorithms to optimize test execution, data handling, and performance validation

- Collaborate in Agile environments, contributing to backlog refinement, sprint planning, and design discussions

**Software Engineering & Development**

- Design, build, test, deploy, and maintain software components, automation frameworks, and validation tools

- Apply strong knowledge of data structures, algorithms, and efficient coding practices in building scalable solutions

- Contribute to end-to-end software development lifecycle, including design, development, testing, deployment, and monitoring

**Architecture & Design**

- Participate in defining software architecture and design patterns to ensure scalability, reliability, and maintainability

- Ensure systems are designed for testability, observability, performance, and operational readiness

- Provide input into microservices and cloud migration strategies

**Quality Engineering & Testing**

- Develop and implement test automation frameworks and CI/CD integration pipelines (e.g., Jenkins, XLR)

- Design comprehensive test strategies and plans, including performance, reliability, and production simulation testing

- Ensure high code quality and coverage using tools such as Sonar or Clover

**Security & Compliance**

- Apply and promote secure coding practices, including code analysis, vulnerability detection, and mitigation strategies

- Integrate security testing into CI/CD pipelines

**Code Quality & Reviews**

- Conduct and lead code reviews, ensuring adherence to coding standards, security practices, and maintainability

- Act as a technical reviewer for system designs, test strategies, and implementation approaches

**Operability & Performance**

- Ensure systems are observable, monitorable, and resilient across environments

- Perform performance engineering, including load testing, tuning, and bottleneck analysis

- Troubleshoot complex production issues and ensure rapid resolution

**Collaboration & Leadership**

- Partner with developers, architects, and product teams to drive engineering best practices

- Mentor junior engineers and contribute to knowledge sharing across teams

- Evaluate and recommend tools, technologies, and frameworks for continuous improvement

**Requirements**

- Experience building applications and REST APIs using Java, Spring Boot, and Spring Data JPA

- Strong foundation in computer science fundamentals, including data structures, algorithms, and object-oriented design

- Ability to write clean, secure, testable code and contribute to unit, service, and integration testing

- Comfort working with SQL and relational data concepts

- Strong analytical and problem-solving skills, with the ability to debug issues and identify practical solutions

- Strong verbal and written communication skills and the ability to work effectively in a collaborative team environment

- Self-motivated, organized, and eager to learn, with a passion for continuous improvement and delivering results

- Strong hands-on experience in software engineering, including development and quality engineering

- Proven experience working with testing across platforms, automation development, and CI/CD integration and deployment

**Preferred Qualifications**

- Experience in cloud and microservices architecture or mainframe modernization

- Experience designing systems for reliability, performance, and scalability

- Domain knowledge in payments and transaction processing systems

- Bachelor's or master's degree in computer science or equivalent experience

## Skills

### Required
- Java
- Spring Boot
- Spring Data JPA
- data structures
- algorithms
- object-oriented design
- SQL
- relational data concepts
- testing across platforms
- automation development
- CI/CD integration and deployment

### Nice to have
- cloud and microservices architecture
- mainframe modernization
- designing systems for reliability, performance, and scalability
- payments and transaction processing systems

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Source: [Apply at mastercard.wd1.myworkdayjobs.com](https://mastercard.wd1.myworkdayjobs.com/en-US/CorporateCareers/job/OFallon-Missouri/Senior-Software-Engineer_R-282821?utm_source=yubhub.co&utm_medium=jobs_feed&utm_campaign=apply)