Senior Software Engineer, Cybersecurity

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 Cybersecurity Software Engineer focused on product security, you will ensure that the firmware, software, and server infrastructure driving our fusion machines are resilient against attack. You’ll work closely with firmware, software, and infrastructure engineers to embed security into every stage of the development lifecycle—reviewing designs, auditing code and dependencies, and integrating security checks into CI/CD pipelines. You’ll lead initiatives in encryption, secrets management, and secure authentication to protect sensitive machine operations. Beyond building defenses, you’ll champion security best practices across the organization, providing both the tools and the guidance to enable engineers to move quickly without sacrificing safety. This role is ideal for someone who wants to blend deep cybersecurity expertise with hands-on engineering to safeguard one of the most advanced energy technologies being built today. This is an onsite role that reports directly to the Lead Electrical Engineer at our Everett, WA office. You Will: - Review firmware, software, and infrastructure designs to identify and mitigate security risks before implementation - Advocate for and implement security best practices across engineering, such as encryption, key rotation, and secure authentication - Deploy and manage application security tools (e.g., Snyk, Trivy, Docker image scanners) to audit dependencies, supply chain risks, and vulnerabilities - Own the definition and enforcement of product-level secrets management and credential handling - Lead initiatives in software and firmware hardening for production systems, ensuring resilience against potential adversarial attacks - Work with firmware, software, and infrastructure engineers to embed security into CI/CD pipelines and development workflows - Create and maintain internal guidelines for secure coding practices and data classification - Contribute to building institutional trust by ensuring our software and firmware meet high standards of security, reliability, and compliance - Serve as the voice of product security in design reviews, code reviews, and cross-functional engineering efforts Required Skills: - Strong Linux systems knowledge, including security hardening and permissions management - Proficiency with Git-based workflows and secure software delivery practices - Solid understanding of modern encryption standards (TLS, AES, RSA, ECC) and key management practices - Hands-on experience with security engineering tools (SAST/DAST, dependency scanning, Docker/Kubernetes security, supply chain auditing) - Experience conducting secure code reviews and identifying common vulnerabilities - Strong programming background in at least two of: C++, Rust, Python, Typescript, or Java - Familiarity with vulnerability assessment and mitigation strategies across firmware, software, and server environments - Ability to work collaboratively with multi-disciplinary en