Software Engineer

We have an opening for a Software Engineer to design, build, and operate secure applications and platforms that help scientists and engineers manage and analyze mission critical data. You will own software across its lifecycle - from architecture and implementation through testing, deployment, and operations - while modernizing existing systems and creating reusable capabilities for multiple LLNL programs. The work spans Python services and REST APIs, modern web interfaces, containerized deployments, scientific visualization, databases, and CI/CD automation. You will partner with scientists, data engineers, and application teams to translate complex workflows into reliable, maintainable software. This is an opportunity to exercise broad technical ownership, influence architecture, and see your work directly support national security missions. You will join a collaborative software engineering team and work across organizational boundaries on shared tools, standards, and integration approaches. Because some work occurs in secure environments, this position requires an on-site presence approximately three to four days per week. This position is in the Applications, Simulations, and Quality Division (ASQ) within the Computing Directorate, supporting Strategic Deterrence application and data management programs. This position may offer a hybrid schedule, which includes the flexibility to work from home one or more days per week, after a probationary period. The specifics of the hybrid schedule, including the exact number of days required in the office and virtual work options may vary based on the needs of the team and the organization. This position will be filled at either level based on knowledge and related experience as assessed by the hiring team. Additional job responsibilities and qualifications will apply if hired at the higher level. You will Design, build, test, deploy, and maintain secure software applications and services supporting scientific and engineering workflows. Own features and technical improvements across the software lifecycle, from requirements and architecture through implementation, documentation, release, and operational support. Design and implement well-documented REST APIs, including appropriate approaches to data modeling, authentication, authorization, versioning, and error handling. Develop usable web interfaces and scientific visualization capabilities using modern frameworks and libraries. Build, deploy, and troubleshoot containerized applications, and contribute to CI/CD pipelines, automated testing, observability, and deployment automation. Partner with scientists, data engineers, and application teams to understand workflows and translate them into maintainable software. Participate in collaborative design discussions and code reviews as both an author and reviewer, giving and receiving constructive technical feedback. Evaluate architectural and technology tradeoffs, including when to use custom software, reusable libraries, commercial products, or platform services. Contribute reusable components, engineering standards, and integration patterns that benefit multiple projects and teams. Communicate technical concepts, risks, tradeoffs, and progress clearly to technical teammates and nontechnical stakeholders. Work with senior engineers and stakeholders to prioritize a portfolio of work, make informed tradeoffs, and deliver the highest value capabilities. Perform other duties as assigned. Additional job responsibilities at the SES.3 level Independently lead the architecture and delivery of complex software systems spanning multiple applications, environments, or stakeholder organizations. Set technical direction, evaluate significant architectural tradeoffs, and provide technical leadership or mentorship across projects. Advise management, customers, and senior technical personnel on software strategy, system design, implementation approaches, and operational risk. Ability to obtain and maintain a U.S. Department of Energy Q-level security clearance, which requires U.S. citizenship. Bachelor’s degree in Computer Science, Computer Engineering, or a related field, or an equivalent combination of education and relevant experience. Broad experience delivering maintainable software using Python, Java, TypeScript, or another modern programming language. Broad experience in several of the following areas: web services and REST APIs, frontend development, databases, containerization, CI/CD, automated testing, scientific visualization, or production operations. Comprehensive experience using Git or an equivalent version control system and participating in collaborative code review. Proficient experience applying software design, testing, documentation, and maintainability practices to production code. Broad experience translating scientific, engineering, or business workflows into software requirements and technical solutions. Proficient written and verbal communication skills and demonstrated ability to collaborate with technical and nontechnical stakeholders. Constructive technical judgment, including the ability to surface risks, challenge assumptions, evaluate alternatives, and build alignment. Additional qualifications at the SES.3 level Advanced experience independently designing and delivering complex software systems from architecture through deployment and operations. Advanced experience providing technical direction, mentoring other engineers, and influencing architectural or process decisions across projects. Advanced experience collaborating with management, customers, or senior technical personnel to recommend and implement systems, services, or process improvements. Qualifications we desire Experience with Python web frameworks (e.g. FastAPI, Flask), modern frontend frameworks (e.g. React, Angular, Vue), and container platforms (e.g. Docker, Kubernetes, OpenShift). Experience building reusable software packages, libraries, APIs, or platform capabilities for scientific or engineering users. Familiarity with data engineering, data governance, semantic technologies, or AI/LLM-enabled applications. Experience working in a national laboratory, U.S. Department of Energy, national security, or other regulated research environment. Pay Range $146,340 - $185,544 Yearly for the SES.2 level $175,530 - $222,564 Yearly for the SES.3 level 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. All your information will be kept confidential according to EEO guidelines. Position Information This is a Career Indefinite position, open to Lab employees and external candidates. 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 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. 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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.