LMI is seeking a skilled Software Development Engineer in Test (SDET) (Mid/Senior) 

to build and scale automated testing capabilities across a distributed modeling and simulation system. The SDET will work alongside developers, DevOps, and domain experts to ensure that deliverables are reliable, secure, and validated at all layers: from low-level services to user-facing applications.

LMI is a new breed of digital solutions provider dedicated to accelerating government impact with innovation and speed. Investing in technology and prototypes ahead of need, LMI brings commercial-grade platforms and mission-ready AI to federal agencies at commercial speed.

Leveraging our mission-ready technology and solutions, proven expertise in federal deployment, and strategic relationships, we enhance outcomes for the government, efficiently and effectively. With a focus on agility and collaboration, LMI serves the defense, space, healthcare, and energy sectors—helping agencies navigate complexity and outpace change. Headquartered in Tysons, Virginia, LMI is committed to delivering impactful results that strengthen missions and drive lasting value.

This role emphasizes test automation, system integration validation, and reliability engineering. You’ll own test strategy, frameworks, and tooling to continuously improve coverage, speed, cycle times, and confidence in our software releases. Space or missile defense domain knowledge is not required but is considered a plus. Familiarity with satellite operations, communications, orbital mechanics, ground systems, or defense systems will help you perform technical validation.

• Design, implement, and maintain automated test frameworks using pytest, Playwright, and other related tools.
• Develop broad (end-to-end/UI) and narrow (API/service) integration tests across distributed services and webapps.
• Leverage Test-containers, k8s, and CI/CD pipelines to provision reproducible, ephemeral test environments.
• Build and maintain characterization tests (Golden Master Testing).
• Build and maintain data-driven validation (schema conformance, contract tests, and/or property-based tests).
• Drive adoption of testability best practices in system designs (dependency isolation, logging, observability hooks/events).
• Support performance, resilience, and security testing as part of the quality strategy.
• Contribute to ongoing Certificate to Field (CTF) processes.
• Partner with DevOps to integrate automated tests into our GitLab pipelines.
• Contribute to post-mortems, root cause analysis, and continuous improvement of reliability.
• Support testing in classified and air-gapped environments with hardened tooling.

Must Have Requirements:

• Bachelor’s degree in Computer Science, Engineering, or equivalent practical experience.
• 5+ year's experience in applicable skills.
• Strong programming skills in Python (pytest, Playwright, httpx, etc.); bonus if comfortable in Go, Rust, or TypeScript.
• Proven experience building automated test frameworks for complex distributed or cloud-native systems.
• Hands-on experience with Kubernetes and test orchestration in CI/CD.
• Familiarity with service integration testing, contract testing, and mocking/virtualization tools.
• Knowledge of performance, load, or chaos testing approaches and tools (e.g., Locust, k6, Toxiproxy, LitmusChaos, ChaosMesh).
• Excellent problem-solving, debugging, and systems thinking skills.
• Strong collaboration and communication experience with development, QA, and operations teams.
• Eligible for DoD Top Secret SCI clearance

Preferred Requirements:

• Master's degree in relevant field
• Space domain knowledge (satellite ground systems, orbital dynamics, RF links, mission operations, or Space Force/DoD programs).
• Experience with secure software development (STIG, FIPS, and/or FedRAMP).
• Exposure to high-performance computing (HPC), simulation frameworks, or war-gaming environments.
• Active security clearance 

Target salary range: $99,162 - $189,108. Final compensation will be determined by a variety of factors including but not limited to your skills, experience, education, and/or certifications.