Senior Software Development Engineer in Test (SDET)

About T-Mobile

At T-Mobile, we believe in investing in our employees! Our Total Rewards Package ensures that our staff receives comprehensive support just as we do for our customers. Enjoy a competitive salary, stock grants, an employee stock purchase plan, a 401(k), and access to year-round financial coaching. This is what makes us UNSTOPPABLE for our employees!

The Senior Software Development Engineer in Test (SDET) is crucial to leading and enhancing quality engineering efforts for T-Mobile's Fiber and High-Speed Internet (HSI) broadband products. This role blends test leadership, insight into execution, and advanced automation expertise to ensure the highest quality standards across customer experiences and backend systems.

As a Senior SDET, you will oversee end-to-end validation of broadband services—from service provisioning to customer account management—while mentoring a diverse team of onshore and offshore QA engineers. You will design and implement scalable automation frameworks that validate real customer journeys, impacting the organization's quality standards and supporting continuous delivery through collaboration and best practice leadership.

This hybrid position requires a minimum of 3 days per week in the office.

Responsibilities

• Establish and drive test strategy and execution for Fiber and HSI services, ensuring thorough coverage of customer experiences, from order eligibility to activation.
• Lead and mentor both onshore and offshore teams to manage sprint planning, test execution, defect tracking, and quality assurance across releases.
• Design, develop, and maintain advanced automation frameworks for UI and API layers to optimize testing of broadband platforms.
• Collaborate with product, engineering, and operations teams to ensure comprehensive, testable requirements and engage in root cause analysis to enhance service quality.
• Integrate automated test suites into CI/CD environments to enable continuous testing and enhance deployment confidence.
• Take on additional projects as requested by business management.

Knowledge, Skills, and Abilities

• Leadership in Agile methodologies, managing sprint planning and onshore/offshore QA coordination.
• Expertise in validating end-to-end customer experiences in broadband (eligibility, ordering, installation, etc.).
• Strong ability to define test strategies and quality metrics.
• Proficient in designing automation frameworks across UI and API layers (e.g., Selenium, Cypress, RestAssured, Postman).
• Experience with complex customer journey automation and enhancing test coverage.
• Strong programming background (Java or similar) and familiarity with modern testing frameworks (e.g., TestNG) and tools (e.g., IntelliJ, Maven, Git/SVN).
• Experience in API and microservices testing in distributed systems.
• Knowledge of connected home devices and their interaction with broadband services.
• Proven problem-solving skills and experience in driving defect resolution.
• Ability to use quality metrics to improve product quality.
• Excellent collaboration and communication skills, working effectively across teams.
• Aptitude for mentoring QA engineers while promoting best quality engineering practices.

Qualifications

• Bachelor's degree plus 5 years of relevant experience, or an advanced degree with 3 years of relevant experience in Software Engineering, Computer Science, or a similar field.
• 4+ years of experience in 3 or more programming languages (e.g., C#, Java, JavaScript) and automation tools (e.g., Selenium, TestNG, Appium).
• 4+ years of knowledge in testing methodologies like Test Driven Development and Behavior Driven Development.
• 4+ years of experience with CA Service Virtualization or a similar platform.
• 4+ years working with issue-tracking software and agile project management.
• 4+ years of designing and developing applications in Unix/Windows environments or mobile platforms.
• At least 18 years old.
• Legally authorized to work in the United States.

Travel may be required.

Compensation

Base Pay Range: $89,400 - $161,300. Corporate Bonus Target: 15%.

Benefits

We offer a competitive benefits package, including medical, dental, and vision insurance, a flexible spending account, 401(k), employee stock grants, and paid time off, among many others. To learn more about T-Mobile's benefits, visit the T-Mobile benefits page.

Diversity and Inclusion

We're committed to fostering a diverse and inclusive environment. We do not tolerate discrimination or harassment based on any characteristic protected by law.

Join us at T-Mobile and discover a career path that doesn’t have a traditional ladder but instead offers a variety of growth opportunities!