Senior Software Engineer, Design in Test (SDET)

Senior Software Test Engineer
About Us:
BlackSky is a real-time intelligence company. We own and operate the world's most advanced space-based intelligence platform and provide customers satellite imagery, automated analytics and high-frequency monitoring of strategic locations, economic assets and events from around the globe. BlackSky is trusted by the most demanding allied military and intelligence organizations and commercial companies to deliver foresight into critical matters that affect national security and the economy. BlackSky's data enables governments and businesses to see, understand and anticipate change as it happens, giving them the ultimate strategic advantage so they can act quickly. Our global team works with cutting-edge technology to make a difference around the world and prides itself on being people-first, customer-focused and fun.
The Software Development Engineer in Test (SDET) is responsible for designing and implementing automated test frameworks, tools, and simulated environments that ensure the reliability and quality of our enterprise software systems. This role is development‑focused and centers on building test harnesses, emulating third‑party systems and network conditions, and creating robust automation infrastructure that enables comprehensive in‑house validation. The SDET develops reusable test code, service/API simulators, and scalable Python‑based frameworks that integrate into CI/CD pipelines to deliver consistent and repeatable coverage across complex application workflows. In addition to building automation systems, they analyze system behavior, investigate failures, collaborate closely with developers, and validate fixes to drive overall product stability and release confidence.
The preferred location is Tukwila, WA with the ability to work in the Tukwila office 1-2 days a week but we may be open to strong remote candidates.
Responsibilities:
Design, develop, and maintain automated test frameworks and tools using Python, enabling scalable and reliable testing across services, APIs, and UI workflows.
Build Python or Go based simulators, mocks, and emulators to replicate third‑party environments, network behavior, and integration scenarios for in‑house testing.
Develop, maintain, and execute automated API test suites using Python Requests, custom harnesses, and Postman/Newman when appropriate.
Build and maintain automated UI test suites using Python Playwright, with a focus on reusable components, selectors, and page‑object patterns.
Monitor nightly automated test runs, analyze failures, and provide actionable insights through integrations with Jira/X‑Ray, Slack, and CI/CD pipelines.
Troubleshoot and diagnose issues across APIs, backend services, and UI workflows, collaborating with developers to isolate root causes and verify fixes.
Perform targeted manual testing for new feature development, complex regression scenarios, and defect reproduction where automation is not yet feasible.
Validate functional behavior, edge cases, and system workflows across distributed application components.
Document test frameworks, automation patterns, test cases, expected outcomes, and reproduction steps for defects.
Support and improve internal Python‑based test applications, tools, and services used in daily verification workflows.
Ensure adequate test coverage for new features, releases, and high‑risk areas.
Contribute to continuous improvement of automation tooling, coding standards, and test strategy.