Senior Algorithms and Simulation Software Engineer
Software Engineering
Devens, MA, USA
Posted on Aug 21, 2026
About Commonwealth Fusion Systems:
Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.
Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers, suppliers, and many others to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading fusion company in the world.
Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.
If that’s you and this role fits, we want to hear from you.
Join the power movement as a Senior Algorithms and Simulation Software Engineer
In this role you will be responsible for the design and implementation of state estimation and control algorithms, plus models and simulation frame works necessary to verify those algorithms. Your algorithms will be used in critical real-time applications in the SPARC project, as well as related projects.
As a member of the Software Engineering team, you will be a hands-on technical contributor. You will be a champion of writing excellent quality, production-ready code for mission-critical real-time systems. You will collect functional requirements from customers and produce software solutions to meet these requirements.
You will work with a variety of engineers to integrate your software into software testbeds, hardware testbeds, and the production tools. You will also contribute to the broader software ecosystem to improve tooling and processes used across the company.
What you'll do:
- Develop mission-critical state estimation and control algorithms
- Develop software infrastructure to operate Hardware-in-the-Loop (HITL) and software-only testbeds
- Develop simulation models and model infrastructure for both real-time and off-line (high fidelity) simulations
- Develop offline data analysis tools
- Help define and execute end-to-end and other integrated test cases and test plans to validate SPARC control software
What we’re looking for:
- Bachelor's degree in a relevant engineering field (computer science, computer engineering, electrical engineering, industrial engineering, etc.)
- 7+ years relevant experience
- Professional experience writing real-time state estimation and control algorithms
- Professional experience writing production quality state estimation and software
- Experience with modern software development lifecycle practices (CI/CD, git version control, unit testing, integration testing, etc)
- Proficiency with python
- Proficiency with at least one real-time control language (c++, rust, etc)
Bonus points for:
- Experience with Hardware-in-the-Loop testbeds and software-only testbeds for validating control software
- Experience writing models to validate software
- Familiarity with Linux
- Familiarity with general networking (IP/UDP)
Must-have Requirements:
- Perform activities such as typing, standing, sitting, etc. for extended periods of time
- Dedication to safety to mitigate industrial hazards that may include heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, high current, pressure systems, and cryogenics
- Willingness to occasionally travel or work required nights/weekends/on-call
#LI-Hybrid
At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.
We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.
This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.
140000 - 200000 USD a year
Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations. Benefits include:
• Competitive compensation with equity
• 13 Company-wide Holidays
• Flexible vacation days
• 10 sick days
• Generous parental leave policy
• Health, dental, and vision insurance
• 401(k) with employer matching
• Professional growth opportunities
• Team-building activities