Principal Software Development Engineer in Test

US Mobile is building the future of wireless communication. The goal: one unified network open to any person and any device, worldwide. Connection without walls.

We’re getting there by empowering customers. All three major networks on one phone and one plan, plus home internet from Starlink. No lock-in. No commitments. Custom fit plans at every price point. 24/7 customer support with real people, empowered to help. We get real-time feedback from Reddit, surveys, and customer support informing product roadmaps and everything we do. It’s working — Consumer Reports named us the top-rated mobile carrier two years in a row.*

And we’re building innovative systems that scale. A network agnostic tech stack. Agile, cross-functional teams built on trust and mutual respect. This work isn’t for everyone. If you work fast, flexibly, and collaboratively — without compromising standards — we want to hear from you.

US Mobile is looking for a Principal-level SDET to own and elevate our quality engineering practice. This is a technical leadership role for someone who has built, scaled, and stabilized automated test platforms in modern microservices environments.

You’ll lead by example, designing test strategy, improving CI pipelines, mentoring engineers, and ensuring quality is embedded across the SDLC.

Technical Leadership

• Own test architecture and automation strategy across backend and frontend systems.
• Design, build, and maintain scalable automated test frameworks.
• Lead end-to-end, API, integration, and UI automation.
• Drive adoption of best-in-class testing practices

Hands-on Execution

• Build and maintain pipelines using Selenium, Playwright or Cypress. (Currently using Cypress)
• API testing.
• Improve test stability, performance, and execution time in CI/CD.
• Actively debug flaky tests and CI failures

Platform & System Focus

• Test Java / Spring Boot microservices.
• Validate async workflows (RabbitMQ).
• Test data persistence layers (MongoDB).
• Ensure quality in AWS-based distributed systems.
• Partner with DevOps to improve pipelines and observability.

Mentorship & Influence

• Mentor Software Engineers on test design and automation.
• Establish coding standards and review practices for test code.
• Influence product and engineering leaders on quality risk and release readiness

Must Have

• 5+ years in Quality Engineering / Test Automation.
• Senior or Staff-level experience in a product-driven org.
• Deep expertise with Selenium, Playwright, Cypress.
• Strong Java background (writing production-quality test code).
• Experience testing microservices & distributed systemsCI/CD experience (GitHub Actions, Jenkins, GitLab, etc.).
• Strong Linux fundamentals.
• Proven ability to lead and influence.

Strong Plus

• Contract testing (Pact or similar).
• Performance testing experience.
• Cloud-native testing in AWS.
• Observability-driven testing (logs, metrics, traces).
• Prior experience building QA orgs from messy to mature

Benefits

• Competitive salary
• Flexible working hours
• Supplemental health insurance
• Professional development stipend
• $500 wfh tech set-up reimbursement

$140,000 - $180,000 a year

Think you could be a good fit?? Apply to learn more!!

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.