Sr. Software Test Engineer

MKS Instruments•Milpitas, CA

About The Position

As a Sr. Software Test Engineer in the Lasers Business Unit at MKS Instruments, you will partner with Spectra-Physics scientists and engineers across software, electrical, and systems disciplines to help ensure the quality of software and systems for new free-space and fiber-based laser systems. You will develop and execute test strategies and report to the Sr. Manager, Software Engineering. The role covers embedded firmware and GUI testing, performance and compatibility testing, defect investigation, test automation, requirements traceability, risk management, and troubleshooting customer-facing issues. Work is performed in a lab or office setting, with prolonged sitting. The salary range is $110,000–$155,000 per year. The position is eligible for a discretionary annual bonus. MKS offers medical, dental, and vision insurance; a 401(k) with company match; life and disability insurance; 12 paid holidays; sick time; 15 paid vacation days; six weeks of fully paid parental leave; adoption assistance; and tuition reimbursement.

Requirements

Bachelor’s degree in Software Engineering, Computer Engineering, Electrical Engineering, or equivalent.
At least 5 years of related software QA experience with embedded systems and GUIs.
Demonstrable proficiency programming in C/C# and Python.
Experience with testing frameworks such as Unity, Pytest, GTest, NUnit, or xUnit.
Proficiency with CI/CD tools, version control, and bug-tracking systems such as JIRA.
Familiarity with I2C, SPI, RS-232, RS-485, Ethernet, and USB interfaces.
Experience with test equipment such as DVMs, power supplies, and oscilloscopes.
Excellent communication, documentation, and organizational skills.

Nice To Haves

Experience working with precision equipment, preferably in the photonics industry.
Exposure to DevSecOps and cybersecurity principles.
Experience using LLMs or other AI tools for test-case generation, test-data creation, or defect analysis.
Ability to read electronic schematic diagrams and component datasheets.
Experience with real-time operating systems such as Azure/ThreadX or FreeRTOS, and/or Linux.
Experience working with distributed teams.

Responsibilities

Develop, maintain, and execute structured manual and automated test plans and cases for embedded firmware at feature, integration, and system levels.
Validate GUI usability, functionality, responsiveness, and compatibility with target hardware and operating systems.
Test software efficiency on embedded platforms and its integration with hardware, firmware, and photonics modules.
Document defects, trace them to requirements, and collaborate with developers to resolve them.
Use automated tools for regression, functional, and GUI testing to improve speed and coverage.
Maintain traceability matrices linking requirements to test cases and results.
Identify failure modes early to prevent costly late-stage fixes.
Reproduce, troubleshoot, and thoroughly test field-reported and customer-facing bugs in live or simulated environments.