Senior Full Stack Engineer

Sphinx Defense · El Segundo, CA · Remote

Posted 8/25/2026 · last confirmed live 8/26/2026

ABOUT SPHINX Sphinx builds software to solve complex national security problems in Space. Founded by engineers and technologists with deep experience across commercial and defense technology, we were frustrated by the outdated and insecure technology America's service members are forced to rely on. We're here to do better.  We’re focused on building modern, scalable products with an emphasis on using open source technologies. Expect talented, motivated, and interesting colleagues who emphasize collaboration, transparency, and individual responsibility. ABOUT SPHINX Sphinx builds software to solve complex national security problems in Space. Founded by engineers and technologists with deep experience across commercial and defense technology, we were frustrated by the outdated and insecure technology America's service members are forced to rely on. We're here to do better.  We’re focused on building modern, scalable products with an emphasis on using open source technologies. Expect talented, motivated, and interesting colleagues who emphasize collaboration, transparency, and individual responsibility. ABOUT THE ROLE Sphinx is hiring a  Senior Full Stack Engineer to join our team, building the next generation of mission planning and command and control software for space communications programs. This team is tasked with creating modern, resilient services and capabilities to service the US Government. As our engineering organization continues to scale rapidly, you’ll also play an important role in helping establish strong technical practices, supporting a growing team, and maintaining quality and consistency as we expand. As a Senior Full Stack Engineer , you will lead the development of intuitive UI/UX and enhance backend services to support Sphinx's space vehicle mission planning platform, which is being leveraged by some of the most important space missions operated by the US Government. We're seeking an experienced engineer with strong front-end development skills AND backend programming fundamentals. You'll work as an individual contributor and a lead for more junior engineers. What you will be focusing on: Building performant, secure, tested web applications with a focus on automation and security Designing, enhancing, and improving APIs between front-end and backend software services Leading the development of critical features across the entire development lifecycle, with significant influence from user feedback, system requirements, design engineering, and evolving customer needs at scale. Conducting thorough code reviews to maintain code quality, enforce best practices, and ensure code adheres to established standards  Creating and translating design mockups into functional, visually appealing user interfaces using modern front-end frameworks (FastAPI, SQLAlchemy, PostgREST, Svelte, React, CesiumJS) and technologies like Python, Javascript, Typescript, CSS, and Kubernetes Advocating for improvements to product quality, security, and performance that have a particular impact on your team and others Supporting junior engineering talent with mentorship or technical guidance You might be a good fit if you have: 5+ years of progressively responsible web development experience with modern software development approaches  Extensive experience with JavaScript, HTML, CSS, TypeScript, web frameworks (React, Svelte), and concepts such as caching, authentication, and CSP Deep understanding of open architecture constructs (e.g., OMS, UCI, OCI) and modern containerized microservices architectures (Docker, Kubernetes) You are a well-rounded engineer comfortable wearing multiple hats, such as a web designer, UX designer, and engineer You possess a strong understanding of backend code with experience integrating the front-end and the backend (and the willingness to fix the backend when it's needed) You are comfortable working with ambiguity and can self-direct your work while guiding others and supporting project leadership activities You understand the importance of, and you have the desire to own a technical problem end-to-end You've made enough mistakes and booked enough wins to know what not to build and what good looks like Excellent communication skills, working with end-users to design and build solutions to their needs, a habit of self-directed learning of new technologies, and the ability to learn quickly and adapt to a fast-paced environment Experience developing, testing, and deploying software within air-gapped or highly secure government network environments. Must be eligible to obtain and maintain TS/SCI access. Bonus points if you have the following:  You have experience designing and developing intuitive user interfaces featuring real time, 2D/3D geospatial visualizations Currently hold an active U.S. Government Secret Clearance LOCATION While this role is remote, the potential for travel may occur such as client visits, company gatherings, and other project related travel as needed may be required. COMPENSATION This role is between $157,000 - $190,000 base salary. BENEFITS Compensation includes competitive salary, meaningful equity ownership, profit sharing, employer 401(k) contribution, and 100% employer covered medical, dental, and vision insurance for you and your dependents. ELIGIBILITY Must be a US Citizen and be able to obtain and hold a U.S. Top Secret security clearance and be eligible to obtain and maintain a TS/SCI clearance . EEO STATEMENT At Sphinx Defense, we are devoted to building a team that represents a variety of backgrounds, perspectives, and skills. Sphinx Defense is committed to providing equal employment opportunities to all employees and applicants for employment without regard to race, color, religion, sex, sexual orientation, and gender identity.   CLEARANCE ELIGIBILITY - This position requires eligibility to obtain and maintain a U.S. security clearance. For more information about U.S. Security Clearances:  click here .    To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State. Learn more about the ITAR  here .  

This role is published by Sphinx Defense on greenhouse. SwiftFit is not the employer and does not accept applications.