Software Test Engineer Jobs in Issaquah, WA (NOW HIRING)

About Endurance
Endurance is building the world's first modular subsea geothermal power plants, converting vast thermal resources under the ocean into gigawatts of baseload power. Backed by Founders Fund, Felicis, First Round Capital, and Point72 Ventures, our founding team includes veterans from SpaceX, Helion, Blue Origin, and Apple. We have completed multiple deep-ocean deployments to subsea volcanoes and are launching a long-term demonstration project this fall. By leveraging modular design, manufacturing scale, efficient drilling, and latent cooling on the seafloor, we are pioneering a new category of energy that outperforms traditional sources on environmental impact, deployment speed, and cost.
What you'll be doing
As a Senior Test Infrastructure Software Engineer at Endurance, you will build the software, controls, and electrical infrastructure that allows our engineering team to rapidly validate every component and every subsystem that goes into a subsea geothermal power plant.
This is not a traditional test software role. One day you may be wiring sensors into a valve test stand, integrating DAQs and PLCs, or bringing up a new electrical system. The next day you may be writing Python services, building hardware-in-the-loop (HITL) simulations, architecting automated test frameworks, or developing software that injects faults to break our control systems before the ocean does.
We believe great test infrastructure is one of the highest leverage investments we can make as an engineering organization. Every improvement you make increases the speed at which mechanical, electrical, firmware, and controls engineers can design, test, iterate, and deploy hardware. Your job is to build the software and hardware ecosystem that enables that acceleration.
You will work directly with firmware, electrical, mechanical, and test engineers to understand what they are building, identify how it should be tested, and rapidly create the infrastructure needed to answer critical engineering questions. In the near term, that means standing up component qualification rigs, building automated valve and pump test systems, developing simulation environments for embedded software, integrating industrial controls hardware, and creating the first generation of Endurance's unified testing platform.
As our systems become more integrated, you will build the infrastructure that validates complete power generation systems. You will design distributed test software, develop hardware-in-the-loop environments capable of simulating real operating conditions and failure modes, and build the data acquisition and visualization systems that allow engineers to understand system behavior in real time.
The ideal candidate is an exceptional software engineer who enjoys working close to hardware. You should be equally comfortable designing software architecture, integrating industrial control systems, writing simulation software, debugging embedded interfaces, and grabbing a crimper or oscilloscope when that's the fastest way to get the test running.
You will be one of the first software engineers focused on test infrastructure at the company. You will work directly with the founding team and engineering leadership across Endurance, and as the function grows, you will have significant influence on the testing architecture, engineering standards, and future hires.
Key Responsibilities

• Design and build the software infrastructure that powers testing across Endurance, from component qualification through full integrated system validation
• Architect and implement hardware-in-the-loop (HITL) and simulation environments that allow firmware and controls software to be tested under realistic operating conditions and failure scenarios
• Develop software for automated test execution, operator interfaces, data acquisition, visualization, storage, and analysis
• Design and integrate the electrical and controls infrastructure behind new test systems, including DAQs, PLCs, VFDs, sensors, instrumentation, and industrial communication networks
• Partner closely with firmware, electrical, mechanical, controls, and systems engineers to rapidly develop new testing capabilities
• Build scrappy one-off test systems when speed matters, then evolve successful concepts into scalable engineering infrastructure
• Write production-quality software while establishing the architecture and engineering patterns that future test systems will build upon
• Own the technical foundation of Endurance's testing ecosystem as it grows from individual laboratory experiments to full power plant validation
• Help shape the test infrastructure organization as it grows, including interviewing and onboarding future engineers

Qualifications

• 5+ years of software engineering experience
• Track record building software for hardware systems, including automated testing, hardware-in-the-loop (HITL), industrial controls, robotics, aerospace, automotive, or other complex electromechanical products
• Strong software engineering skills, particularly in Python, with experience in C, C++, Rust, or similar systems programming languages preferred
• Experience interfacing software with physical hardware, instrumentation, embedded systems, or industrial equipment
• Technical fluency strong enough to hold credibility with mechanical, electrical, firmware, and systems engineers
• Comfort working hands-on in the lab, including wiring sensors, debugging electrical systems, integrating instrumentation, and bringing up new test hardware
• Ability to work onsite in Seattle and travel to deployment sites as required

Preferred Skills

• Experience building hardware-in-the-loop (HITL) or software-in-the-loop (SITL) environments
• Experience with industrial automation platforms including PLCs, DAQs, VFDs, National Instruments, Beckhoff, Siemens, or similar systems
• Experience developing simulation or emulation software for embedded or controls applications
• Familiarity with industrial communication protocols such as EtherCAT, CAN, Modbus, or OPC UA
• Experience designing data acquisition and telemetry systems for hardware development
• Background in aerospace, robotics, automotive, energy, defense, or other fast-paced hardware industries
• Experience building internal engineering infrastructure that enables other engineers to move faster

Compensation, Benefits, & Perks
As a pre-revenue startup, Endurance Energy offers competitive base salaries and generous equity packages for full-time employees. Final base salary will be determined by an array of factors including internal equity, job-related knowledge, skills, and work experience.
A key aspect of our compensation philosophy is that value creation should be aligned with rewards. Right now this means equity is a significant portion of every full-time employee's compensation. As the company matures, there will be continued evolution and changes to the total rewards and total compensation package. What will always be true is that if we win, we win together. Equity is granted to every full-time employee as a meaningful piece of ownership. We believe the people building the company should share directly in the value they create.
In addition to a competitive base salary and equity, employees will receive all of our other great benefits and perks, including:

• Benefits: Health, Dental, and Vision insurance coverage
• Time Away: Flexible PTO including 12 paid company holidays
• Global Fieldwork: Travel to fascinating deployment sites along oceanic ridges in locations like the Pacific Northwest, Hawaii, Iceland, Japan, New Zealand, and the Azores
• Hands-on Experience: Participate in sea trials and deployment operations in partnership with leading oceanographic institutions
• Cutting-edge Development: Work with technology that spans high-power electronics, marine systems, and clean energy
• Impactful Work: Help solve one of the world's most pressing challenges
• Dive Certification: Company-sponsored recreational dive certification
• Other Perks: Access to the company boat, free meals and snacks, and the list goes on!

If you're selected for consideration, a recruiter will be able to discuss in greater detail.