Python Software Developer Jobs in California (NOW HIRING)

Join us and make YOUR mark on the World!

Lawrence Livermore National Laboratory (LLNL) has turned bold ideas into world-changing impact advancing science and technology to strengthen U.S. security and promote global stability. 

Our mission spans four critical national security areas nuclear deterrence, threat preparedness, energy security, and multi-domain defense empowering teams to take on the toughest challenges of today and tomorrow. With a culture built on innovation and operational excellence, LLNL is a place where your expertise can make a real impact.

Are you energized by the challenge of building robust data management systems that become the backbone of critical scientific work? Do you light up at the intersection of solid software engineering and cutting-edge AI capabilities? We're seeking a software engineer who shares our excitement for creating elegant, scalable data solutions while pushing the boundaries of what's possible with artificial intelligence. This is your opportunity to work on systems where traditional engineering excellence meets the transformative potential of AI.

We are seeking a Python Software Engineer to design and develop discrete and continuous scientific simulation software supporting complex industrial and physics-based modeling efforts. This role sits at the intersection of software engineering and scientific computing, working across projects at varying stages of maturity - from early prototypes to production-grade tools. You'll work closely with scientists, engineers, and domain experts to translate evolving scientific requirements into robust, well-architected, and maintainable software.

This position is within the Global Security Computing Applications Division (GS-CAD) of the Computing Directorate, matrixed to the Global Security Directorate.

This position offers a hybrid schedule, blending in-person and virtual presence. You will have the flexibility to work from home up to 2, and at times 3, days per week.

You will

• Guide the completion of projects and contribute to the design, development, test, maintenance, and deployment of scientific computation and simulation libraries and tools.
  • Support multiple deployment pathways, including desktop, containerized, and HPC/cluster environments.
  • Contribute to the design and build data visualization and analysis tools to assist scientists interpret simulation results.
  • Integrate simulation and computation libraries with other platforms, applications, and data pipelines.
• Troubleshoot issues that span software, computational methods, and scientific/engineering domains.
• Collaborate with multidisciplinary teams including scientists, engineers, and other developers to gather requirements, participate in design reviews, and deliver high-quality solutions to complex problems.
• Contribute to software quality assurance, including defining test strategies, reviewing test coverage, and ensuring compliance with project and organizational software standards.
• Support the transformation of conceptual and physics-based models into well-structured, extensible software as scientific understanding matures.
• Perform other duties as assigned.

• Ability to secure and maintain a U.S. DOE Q-level security clearance, which requires U.S. citizenship.
• Bachelor's degree in computer science, software engineering, or a related technical discipline, or an equivalent combination of education and relevant experience.
• Advanced knowledge of and hands-on experience with Python, including scientific computing libraries (e.g., NumPy, SciPy, pandas).
• Advanced object-oriented design and implementation skills, with experience architecting maintainable, extensible codebases.
• Demonstrated experience applying solid software engineering practices, such as, clean code, testing discipline, documentation, and code review, to build scalable and secure software.
• Advanced experience with Git or an equivalent modern version control system.
• Ability to work independently on ambiguous or complex problems, exercising sound technical judgment, taking initiative to develop effective solutions, and documenting designs.
• Advanced written and verbal communication skills, necessary to effectively collaborate in a team environment and present and explain complex technical information and provide advice to management.

Qualifications We Desire

• Master's degree in computer science, computer engineering, or a related technical field.
• Experience with C/C++, particularly for performance-critical or legacy scientific code integration.
• Familiarity with scientific/numerical modeling concepts (e.g., differential equations, discrete-event simulation, or physics-based simulation).
• Experience with HPC job schedulers (e.g., Slurm) or parallel/distributed computing.
• Experience with data visualization frameworks (e.g., Matplotlib, Plotly, VTK, ParaView).
• Experience with CI/CD pipelines and containerized deployment (Jenkins, Docker, Kubernetes).
• Experience working in a national lab, DOE, or other regulated/classified research environment.

Pay Range

$175,530 - $222,564 Annually

This is the lowest to highest salary we in good faith believe we would pay for this role at the time of this posting; pay will not be below any applicable local minimum wage.  An employee's position within the salary range will be based on several factors including, but not limited to, specific competencies, relevant education, qualifications, certifications, experience, skills, seniority, geographic location, performance, and business or organizational needs.

#LI-Hybrid

Position Information

This is a Career Indefinite or At Will appointment. Lab employees and external candidates may be considered for this position.

Why Lawrence Livermore National Laboratory?

• Included in 2026 Best Places to Work by Glassdoor!
• Flexible Benefits Package
• 401(k)
• Relocation Assistance
• Education Reimbursement Program
• Flexible schedules (*depending on project needs)
• Our values - visit https://www.llnl.gov/inclusion/our-values

Security Clearance

This position requires a Department of Energy (DOE) Q-level clearance.  If you are selected, we will initiate a Federal background investigation to determine if you meet eligibility requirements for access to classified information or matter. Also, all L or Q cleared employees are subject to random drug testing.  Q-level clearance requires U.S. citizenship. 

Pre-Employment Drug Test

External applicant(s) selected for this position must pass a post-offer, pre-employment drug test. This includes testing for use of marijuana as Federal Law applies to us as a Federal Contractor.

Wireless and Medical Devices

Per the Department of Energy (DOE), Lawrence Livermore National Laboratory must meet certain restrictions with the use and/or possession of mobile devices in Limited Areas. Depending on your job duties, you may be required to work in a Limited Area where you are not permitted to have a personal and/or laboratory mobile device in your possession.  This includes, but not limited to cell phones, tablets, fitness devices, wireless headphones, and other Bluetooth/wireless enabled devices.  

If you use a medical device, which pairs with a mobile device, you must still follow the rules concerning the mobile device in individual sections within Limited Areas.  Sensitive Compartmented Information Facilities require separate approval. Hearing aids without wireless capabilities or wireless that has been disabled are allowed in Limited Areas, Secure Space and Transit/Buffer Space within buildings.

How to identify fake job advertisements

Please be aware of recruitment scams where people or entities are misusing the name of Lawrence Livermore National Laboratory (LLNL) to post fake job advertisements. LLNL never extends an offer without a personal interview and will never charge a fee for joining our company. All current job openings are displayed on the Career Page under "Find Your Job" of our website. If you have encountered a job posting or have been approached with a job offer that you suspect may be fraudulent, we strongly recommend you do not respond.

To learn more about recruitment scams: https://www.llnl.gov/sites/www/files/2023-05/LLNL-Job-Fraud-Statement-Updated-4.26.23.pdf

Equal Employment Opportunity

We are an equal opportunity employer that is committed to providing all with a work environment free of discrimination and harassment. All qualified applicants will receive consideration for employment without regard to race, color, religion, marital status, national origin, ancestry, sex, sexual orientation, gender identity, disability, medical condition, pregnancy, protected veteran status, age, citizenship, or any other characteristic protected by applicable laws.

Reasonable Accommodation

Our goal is to create an accessible and inclusive experience for all candidates applying and interviewing at the Laboratory.  If you need a reasonable accommodation during the application or the recruiting process, please use our online form to submit a request. 

California Privacy Notice

The California Consumer Privacy Act (CCPA) grants privacy rights to all California residents. The law also entitles job applicants, employees, and non-employee workers to be notified of what personal information LLNL collects and for what purpose. The Employee Privacy Notice can be accessed here.