Senior Software Engineer, Network/Performance

Senior Software Engineer, Network/Performance About Helion We 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 over $1 billion from long-time investors such as Sam Altman, Mithril, and Capricorn Investment Group as well as new investors SoftBank and Lightspeed to propel us forward. Our last prototype, Trenta, completed 10,000 high-power pulses and reached plasma temperatures of 100 million degrees Celsius (9 keV). We are now operating Polaris, our next prototype on the path to the world's first fusion power plant. 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 Software Engineer focused on Network and Performance, you will own the architecture and reliability of the communication networks that connect our fusion machine and plant-scale systems. You’ll design and validate networking solutions that support deterministic control, precise time synchronization, high throughput, and fault-tolerant operation across thousands of devices. You’ll evaluate and deploy networking technologies that enable safe, reliable, and high-performance machine operation. You’ll work closely with security engineers to harden the network against threats, partner with electrical systems/integration engineers to define and manage system interfaces, and collaborate with hardware and software teams to integrate networking requirements into the broader system architecture. This is a hands-on role where you’ll configure switches, prototype new approaches, and rigorously test performance and reliability, ensuring our plant-wide networking is robust enough to scale with the future of fusion. This is an onsite role that reports directly to the Lead Electrical Engineer at our Everett, WA office. You Will: - Own the design, configuration, and operation of machine- and plant-wide networking infrastructure - Define and maintain networking requirements for bandwidth, latency, time synchronization, redundancy, and reliability - Design, test, and validate networking technologies, including Ethernet, Industrial Ethernet, EtherCAT, PTP/NTP, Time-Triggered Ethernet, and emerging precision timing protocols - Configure, prototype, and test industrial switches, routers, and network devices to meet performance and reliability goals - Work with Security Engineers to harden networks, including segmentation, authentication, and intrusion detection - Collaborate with IS&T to define plant-to-enterprise interfaces and ensure integration with corporate systems - Work with Electrical Systems/Integration Engineers on system level requirements, machine integration, and harnessing ICDs - Partner with hardware/software teams to ensure networking requirements are aligned with machine-level controls and performance needs - Monitor, diagnose, and improve network performance, proactively identifying bottlenecks or failure points Required Skills: - Strong background in Linux-based systems administration and networking - Proficiency with Git and modern software development workflows - Deep understanding of TCP/IP networking, VLANs, and switch configuration - Hands-on experience with time synchronization protocols (PTP, NTP) and precision timing architectures - Knowledge of fault-tolerance and redundancy design in industrial or mission-critical networks - Experience with Industrial Ethernet protocols (EtherCAT strongly preferred) - Familiarity with configuring and tuning managed switches, routers, and industrial networking devices - Ability to ... (truncated, view full listing at source)