We are looking for a Senior Software Development Engineer in Test (SDET) to help build and maintain the quality of our web applications. You will work closely with software engineers and product managers to automate testing solutions that enable rapid, reliable software delivery. A major focus of this role is expanding and owning our Cypress end-to-end test suite. You'll help establish testing protocols, improve CI reliability, investigate production issues, and proactively prevent regressions through automation. Apply to join the team if you enjoy writing production-quality code, improving developer workflows, and treating automated testing as a core engineering discipline! Job Responsibilities: - Design, implement, and maintain automated test frameworks and tooling for web applications. - Create reliable, maintainable, and scalable automated tests that run in CI/CD pipelines. - Review requirements and user stories to identify edge cases and improve testability before implementation. - Improve the reliability and performance of our automated test infrastructure by reducing flaky tests and increasing execution stability. - Contribute to engineering standards around testing, code quality, and continuous delivery. - Participate in code reviews and collaborate on improving overall software quality. Education and Work Experience: - Bachelor's Degree plus 5 years of related work experience OR Advanced degree with 3 years of related experience (Required) - Acceptable areas of study include Software Engineering, Computer Science or a related field or the foreign equivalent, and 5 years of progressively responsible postbaccalaureate relevant work experience. (Required) - 4-7 years Professional experience testing web applications in modern development languages (JavaScript TypeScript, Python, etc.). (Required) - 4-7 years Professional experience using 3 or more testing automation tools such as Cypress, Postman, Playwright, etc. (Required) - 4-7 years Professional experience with various testing methodologies and strategies: Test Driven Development, Behavior Driven Development, etc. (Required) Knowledge, Skills and Abilities: - Strong experience with Cypress or similar end-to-end testing frameworks (Playwright, Selenium, WebDriverIO, etc.) (Required) - Experience testing REST APIs using tools such as Postman, Rest Assured, or equivalent (Required) - Experience working with Agile software development teams (Required) - Experience using source control systems (Git) and CI/CD platforms such as GitHub Actions, GitLab CI, or Jenkins (Required) - Strong debugging and troubleshooting skills (Required) - Experience writing end-to-end regression test suites and unit tests alongside application code (Required) - Excellent communication and collaboration skills (Required) - At least 18 years of age - Legally authorized to work in the United States Travel: Travel Required (Yes/No): No DOT Regulated: DOT Regulated Position (Yes/No): No Safety Sensitive Position (Yes/No): No Base Pay Range: $89,400 - $161,300 Corporate Bonus Target: 15% The pay range above is the general base pay range for a successful candidate in the role. The successful candidate’s actual pay will be based on various factors, such as work location, qualifications, and experience, so the actual starting pay will vary within this range. At T-Mobile, employees in regular, non-temporary roles are eligible for an annual bonus or periodic sales incentive or bonus, based on their role. Most Corporate employees are eligible for a year-end bonus based on company and/or individual performance and which is set at a percentage of the employee’s eligible earnings in the prior year. Certain positions in Customer Care are eligible for monthly bonuses based on individual and/or team performance. To find the pay range for this role based on hiring location, https://paylookup.t-mobile.com/paylookup?reqID=REQ356813¶dox=1 At T-Mobile, our benefits exemplify the spirit of One Team, Together! A big part of how we care for one another is working to ensure our benefits evolve to meet the needs of our team members. Full and part-time employees have access to the same benefits when eligible. We cover all of the bases, offering medical, dental and vision insurance, a flexible spending account, 401(k), employee stock grants, employee stock purchase plan, paid time off and up to 12 paid holidays - which total about 4 weeks for new full-time employees and about 2.5 weeks for new part-time employees annually - paid parental and family leave, family building benefits, back-up care, enhanced family support, childcare subsidy, tuition assistance, college coaching, short- and long-term disability, voluntary AD&D coverage, voluntary accident coverage, voluntary life insurance, voluntary disability insurance, and voluntary long-term care insurance. We don't stop there - eligible employees can also receive mobile service & home internet discounts, pet insurance, and access to commuter and transit programs! To learn about T-Mobile’s amazing benefits, check out . Never stop growing! As part of the T-Mobile team, you know the Un-carrier doesn’t have a corporate ladder–it’s more like a jungle gym of possibilities! We love helping our employees grow in their careers, because it’s that shared drive to aim high that drives our business and our culture forward. By applying for this career opportunity, you’re living our values while investing in your career growth–and we applaud it. You’re unstoppable!