Principal Software Development Engineer in Test

US Mobile is on a mission to revolutionize connectivity. Imagine a world where you can go into a single app and buy terabytes of data for every one of your devices: phone, smart devices, car, home broadband, and more. That’s the future that US Mobile is building: a software platform built truly for the 21st century and the age of 5G and IoT, with world class engineering, best‑in‑class user experience, and features that will define the next generation of connectivity.

At the core of it all, we have a team and culture that has been recognized by Forbes as one of the top 500 best startup employers in the US. Our team spans diverse backgrounds, cultures, and stories, with employees coming from 20+ countries.

We’re a venture‑backed company entering hyper‑growth, having recently ranked 94th on Inc 5000’s fastest‑growing private companies in America, and we’re looking for someone exceptional to join our team.

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.

• 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

• 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

• Test Java / Spring Boot microservices
• Validate async workflows (Rabbit
  
  MQ)
• Test data persistence layers (Mongo
  
  DB)
• Ensure quality in AWS‑based distributed systems
• Partner with Dev Ops to improve pipelines and observability

• 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

• 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 systems
• CI/CD experience (Git Hub Actions, Jenkins, Git Lab, etc.)
• Strong Linux fundamentals
• Proven ability to lead and influence

• 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

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

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. 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.