Principal Software Development Engineer in Test

US Mobile•Toronto, ON

2d•$140,000 - $180,000

About The Position

US Mobile is building the future of wireless communication with the goal of one unified network open to any person and any device, worldwide. They are empowering customers with a unique offering that includes all three major networks on one phone and one plan, plus home internet from Starlink, with no lock-in or commitments. They offer custom-fit plans at every price point and 24/7 customer support with real people. US Mobile utilizes real-time feedback from various channels to inform product roadmaps and has been recognized by Consumer Reports as the top-rated mobile carrier for two consecutive years. They are building innovative, scalable systems with a network-agnostic tech stack and agile, cross-functional teams built on trust and mutual respect. This role is for someone who works fast, flexibly, and collaboratively without compromising standards. US Mobile is looking for a Principal-level SDET to own and elevate their quality engineering practice. This is a technical leadership role for an individual who has built, scaled, and stabilized automated test platforms in modern microservices environments. The role involves leading by example, designing test strategy, improving CI pipelines, mentoring engineers, and ensuring quality is embedded across the SDLC.

Requirements

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 (GitHub Actions, Jenkins, GitLab, etc.).
Strong Linux fundamentals.
Proven ability to lead and influence.

Nice To Haves

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.

Responsibilities

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.
Perform 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 (RabbitMQ).
Test data persistence layers (MongoDB).
Ensure quality in AWS-based distributed systems.
Partner with DevOps 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.