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# Senior Software Engineer

- **Company:** Mastercard
- **Location:** O'Fallon, MO, United States
- **Experience:** Expert
- **Salary:** $115,000.0 - $184,000.0
- **Contract:** Permanent contract
- **Skills:** Clean Code Principles, HTML, Java (Programming Language), JavaScript (Programming Language), Application Programming Interfaces (APIs), Agile Methodology, Cascading Style Sheets (CSS), Cloud Computing, Code Review, Cyber Security, Relational Databases, Software Debugging, Distributed Systems, Cloud Services, Prometheus, Software Deployment, Software Engineering, TypeScript, ReactJS, Grafana, Spring-boot, Software Troubleshooting, Apigee, Backend, Agentic-AI, Event Driven Architecture, Containerization, Kubernetes, Infrastructure Automation Frameworks, Information Technology, Apache Kafka, Front End Software Development, Restful APIs, Terraform, Splunk, Dynatrace, Api Management, Docker, Mulesoft, Microservices
- **Published:** October 15, 2026
- **Apply:** https://www.careerjet.com/job/us509e9b71670a7ba760f718408baff7f4/eaa

## About the Role

* Bachelor's degree in Computer Science, Engineering, Information Technology, or a related field, or equivalent practical experience.
 * Agentic AI Development and Spec-Driven Development experience.
 * Experience building enterprise solutions using Java and Spring Boot.
 * Experience developing REST APIs, microservices, and distributed systems.
 * Working knowledge of React, JavaScript/TypeScript, HTML, and CSS.
 * Experience with cloud platforms, relational databases, and CI/CD pipelines.
 * Strong troubleshooting, debugging, and analytical skills.
 * Ability to deliver technical solutions independently while collaborating effectively within a team environment.

Preferred Qualifications

 * Experience with API management solutions such as Apigee, MuleSoft, Kong, or similar platforms.
 * Knowledge of AWS cloud services and cloud-native application design.
 * Familiarity with Kafka and event-driven architectures.
 * Experience with containerization, orchestration, and Infrastructure as Code tools, including Docker, Kubernetes, and Terraform.
 * Exposure to observability, monitoring, and performance management tools such as Splunk, Dynatrace, Grafana, or Prometheus.

## Description

As a Senior Software Engineer, you will design, build, test, deploy, and support full-stack solutions that power these capabilities. Working across the frontend, backend, data, and cloud ecosystem, you will contribute to modern, reliable platforms while helping advance technical excellence and operational maturity.
What You'll Do
Software Development

 * Design, develop, test, and support full-stack applications, APIs, and services.
 * Translate business and technical requirements into maintainable solutions.
 * Build REST APIs, microservices, and user-facing functionality.
 * Write high-quality code that aligns with Mastercard engineering standards.

Design & Architecture

 * Participate in application design and architectural discussions.
 * Contribute to cloud-based, resilient solution designs.
 * Support modernization efforts and technology enhancements.

Quality & Operational Excellence

 * Create and maintain automated unit, integration, and API tests.
 * Participate in code reviews to strengthen quality and maintainability.
 * Troubleshoot production issues, perform root cause analysis, and optimize performance.
 * Support observability, monitoring, CI/CD pipelines, and operational readiness.

Collaboration

 * Partner with Product, Architecture, UX, Security, and Engineering teams to deliver business value.
 * Participate in Agile ceremonies, technical planning, and knowledge-sharing activities.
 * Promote engineering standards and continuous improvement., * A successful Senior Software Engineer will:
 * Deliver features from design through production deployment.
 * Build reliable, high-performing applications and services.
 * Enhance maintainability, performance, and operational efficiency.
 * Demonstrate ownership of key systems or technical domains.
 * Contribute to quality, automation, and engineering excellence.

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.