Senior Firmware Engineer

About HelionWe are a fusion power company based in Everett, WA, with the mission to build the world's first fusion power plant, enabling a future with unlimited clean electricity. Our vision is a world with clean, reliable, and affordable energy for everyone.Since Helion's founding in 2013, we have raised $1.5 billion from long-time investors such as Sam Altman, Mithril, and Capricorn Investment Group as well as new investors including Thrive Capital, LightSpeed Venture Capital, SoftBank, and others to propel us forward. Our current prototype, Polaris, has reached record-breaking plasma temperatures of 150 million degrees Celsius (13 keV). Helion is continuing to iterate and on the path to the world's first fusion power plant, Orion.This is a pivotal time to join Helion. You will tackle real-world challenges with a team that prizes urgency, rigor, ownership, and a commitment to delivering hard truths – values essential to achieving what no one has before. Together, we will change the future of energy, because the world can't wait.What You Will Be Doing:As a Senior Firmware Engineer, you will develop the embedded systems that power the control, diagnostics, and protection layers of our fusion machines. You’ll write and maintain firmware that runs on thousands of distributed embedded devices controlling and monitoring tens of thousands of sensors, actuators, and data channels. This role bridges hardware and software — you’ll work closely with electrical and software engineers to design reliable, scalable, and high-performance control and data acquisition systems. You’ll help define communication protocols, improve time synchronization across embedded networks, and automate hardware bring-up and testing. This position is ideal for an engineer who enjoys working close to the metal, debugging complex systems, and rapidly iterating on real-world hardware to make fusion power a practical reality. This role requires onsite presence, and you will report directly to our Lead Electrical Engineer at our Everett, WA, office.You Will:Develop, test, and maintain firmware for real-time embedded systems used in machine control and diagnostics.Work closely with hardware and software engineers to translate system requirements into embedded designs.Bring up new boards, sensors, and actuators — debugging with oscilloscopes, logic analyzers, and JTAG interfaces.Implement and maintain low-level communication protocols (UART, SPI, I²C, CAN, EtherCAT, etc.).Design and refine embedded command interfaces, configuration utilities, and automated test frameworks.Optimize performance, reliability, and timing synchronization across distributed embedded systems.Contribute to continuous improvement of embedded toolchains, build systems, and test automation.Rapidly prototype novel control and measurement concepts to support new machine architectures.Collaborate across disciplines to ensure firmware integrates seamlessly with high-level software and data systems.Required Skills:BS or higher in Electrical Engineering, Computer Engineering, or Computer Science.8+ years of experience developing embedded systems in C, C++, and/or Rust.Experience with real-time MCU development (bare metal or RTOS-based).Strong understanding of digital communication protocols (UART, SPI, I²C).Familiarity with mixed-signal circuit design and debugging using oscilloscopes, DMMs, and logic analyzers.Experience with version control systems (Git).Scripting experience in Python for automation, hardware bring-up, or testing.Solid grasp of embedded systems fundamentals: power, timing, data, and memory budgets.Experience developing and debugging on Linux-based systems.#LI-Onsite #LI-KL1BenefitsOur total compensation package includes benefits, including but not limited to:Medical, Dental, and Vision plans for employees and their families 31 Days of PTO (21 vacation days and 10 sick days) 10 Paid holidays, plus company-wide winter break Up to 5% employer 401(k) match Short term disability, long term disability, and life insurance Paid parental leave and support (up to 16 weeks) Annual wellness stipendHelion is an equal opportunity employer and value diversity at our company. We do not discriminate based on race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status. If you need assistance or an accommodation during the interview process, please let us know.Compensation Range: $200K - $236KLocationEverett, WAEmployment TypeFull timeLocation TypeOn-siteDepartmentSoftware EngineeringCompensation$200K – $236K