Software Engineer, Digital Twin

Focused Energy Inc.

full-time

Posted on: 12/19/2025

Location Type: Hybrid

Location: San Francisco • California • 🇺🇸 United States

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Mid-LevelSenior

CloudPython

About the role

Build architecture for the digital twin platform, balancing performance, scalability, usability, and scientific rigor.
Design, develop, and maintain high-performance systems code for fusion reactor studies, with an emphasis on modularity, reuse, and long-term maintainability.
Establish and enforce testing, validation, and verification standards to ensure reliability, reproducibility, and trust in simulation results to ensure reliability and robustness
Optimize code for performance and scalability
Professionalize research and prototype code into production-quality software used across teams
Design APIs and interfaces that enable fast iteration and clear communication between simulation, ML, and experimental systems
Improve simulation throughput and turnaround time through performance optimization, parallelization, and scalable infrastructure
Influence how software is built across the company by setting patterns, tooling, and engineering standards
Contribute to the development of a comprehensive software ecosystem for fusion reactor studies
Work closely with experimentalists and technical departments to validate and refine computational models.
Collaborate with other research institutions and industry partners on joint projects
Monitor technological advances in systems code and fusion reactor studies

Comfortable operating in ambiguous, early-stage environments and making architectural tradeoffs with incomplete information
Strong background in software development, engineering and/or computer science, preferably with a strong focus on modeling and simulation
Familiar with the development and management of scalable cloud infrastructure, ideally as used in science, ML or other data processing-heavy use cases
Strong foundation in statistics, computer science and machine learning
Experience building maintainable and testable code bases, including API design and unit testing techniques
Experience with HPC environments and developing scalable simulation workflows
Proficiency in various languages e.g. Python, Fortran, MATLAB, C++

Benefits

Innovative Technology & Mission: Be part of a cutting-edge company working on groundbreaking research in clean energy and scientific discovery.
Career Development: We invest in our people. This is an opportunity to join an early, growing company at the forefront of new technology, where you’ll have the opportunity to develop and grow your career.
Collaborative Culture: Work with great people in a dynamic, international environment with top-tier scientists, engineers and professionals passionate about solving global challenges.
Ownership: Take ownership from day 1 and drive impact by making decisions, solving challenges and shaping the future of our company.
Your Success is our Success: We offer a competitive salary and company ownership in the form of stock options, giving you a direct stake in our success and ownership in what we build together.
Flexibility: We believe work should adapt to your life—not the other way around. That’s why we offer a hybrid setup, giving you the freedom to work from our office while also enjoying the flexibility to work from home when it suits you.
Events: We organize regular events to foster team bonding, encourage collaboration, and build a strong, supportive company culture. Connect with colleagues across departments, share ideas, and have fun together, both in and outside of the workplace.

Tip: use these terms in your resume and cover letter to boost ATS matches.

PythonFortranMATLABC++API designunit testinghigh-performance computing (HPC)performance optimizationparallelizationscalable simulation workflows

collaborationcommunicationproblem-solvingadaptabilityinfluenceleadershiporganizational skillsattention to detailcritical thinkingresearch skills