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Focused Energy is building commercial-scale laser-driven inertial fusion power plants. Backed by a $240M Series A (the largest fully secured Series A in the global fusion industry), the company operates across Germany and the US with top scientific and engineering talent.
You will serve as Principal Software Engineer, defining and owning the Core Software architecture for the fusion power plant. Reporting to the Head of Software, this is a foundational technical role that shapes how controls, hardware interfaces, calibration systems, data infrastructure, and human-machine interfaces integrate into one coherent system.
Key responsibilities:
- Define and maintain end-to-end Core Software architecture, including device interfaces, calibration, data handling, storage, and HMI
- Design and implement critical Core Software components using C++ and Python
- Define clear interfaces between software, control hardware, diagnostics, plant equipment, data systems, and operator tools
- Design reliable automated calibration facilities and workflows producing traceable, repeatable results
- Set practical standards for architecture, coding, testing, observability, documentation, release, reliability, security, and fault tolerance
- Lead technical decisions across teams, mentor engineers, resolve difficult trade-offs, and grow as a technical lead within the Software Department
You will operate as a technical leader within the department, setting engineering standards and shaping the software backbone of a fusion power plant.
REQUIREMENTS (Must-Haves):
- Extensive experience designing and implementing control software for complex physical or industrial systems
- Extensive experience with hardware-software interfaces, device integration, and system-level troubleshooting
- Experience designing and implementing automated calibration facilities or workflows
- Strong experience with data handling, data pipelines, metadata, and reliable data storage
- Experience designing and implementing HMI for operators or technical users
- Strong software design and implementation skills in C++, Python, or similar languages
- Ability to define architecture for complex, mission-critical systems under changing requirements and strict physical constraints
- Strong communication skills explaining technical decisions, risks, and trade-offs to software, hardware, science, and operations stakeholders
- Strong leadership skills: guiding decisions, mentoring engineers, building alignment, taking ownership without formal authority
- Experience applying thorough testing, observability, reliability, fault tolerance, security, and documentation practices
Nice-to-Haves:
- Experience with software for plasma, nuclear power, high-energy physics, or scientific facilities
- Experience with real-time or distributed control systems and high-throughput data acquisition
- Experience defining shared frameworks, API conventions, configuration management, or communication systems for multiple teams
- Experience writing architecture decision records or technical proposals and leading architecture reviews
- Experience growing into a department-level technical lead or coaching senior engineers
- Fluency with AI-assisted software development or strong enthusiasm for using approved AI tools responsibly
