Senior Software Engineer with Security Clearance

ExistX was founded to bridge the technology 'valley of death'-the critical gap between groundbreaking research and real-world solutions. Our team excels in applied engineering, transforming cutting-edge advancements in cryptography, cyber-physical systems, and automated reasoning into practical tools for both government and commercial applications. We leverage a unique suite of capabilities-incubated through our sister R&D firm, Galois, and key research partnerships-to rapidly prototype and deliver impactful solutions. X.P(X): For every problem (X), a solution exists (P). The solution exists. Let's build it together. The Role
In this role, you will rapidly prototype new capabilities, create performant backend services, and collaborate to translate complex, cutting-edge software designs into software solutions for mission-critical systems. Engineers collaborate with cross-functional teams of clients, partners, ExistX employees, and domain experts to design, develop, implement, and deploy advanced algorithms and software systems.
Responsibilities
• Translate complex research designs into seamless, high-performance software applications
• Design and implement complex software components and services, including network-aware backend systems
• Develop and integrate networking protocols and APIs at the Session Layer (Layer 5), such as custom authentication, connection management, and data exchange mechanisms
• Collaborate with cross-functional teams of experts to implement modern software engineering and network best practices
• Contribute to secure and reliable system architectures for distributed or networked environments
• Mentor developers and provide hands-on technical guidance
• Help drive the technical roadmap with a focus on scalable, network-resilient systems
Key Qualifications
• BS in Computer Science or related field
• 5+ years professional software development experience
• Expertise with backend development in Rust, C/C , Python, Java, or similar languages
• Understanding of networking protocols and architectures (TCP/IP, TLS, HTTP/S, WebSockets, gRPC)
• Experience developing scalable, session-aware systems capable of handling large data sets
• Familiarity with Layer 5 network development, including protocol negotiation, session tracking, and stateful connection handling
• Experience building distributed systems, peer-to-peer applications, or secure communications platforms
• Passion for writing high-quality, high-performance code
• TS/SCI with full-scope polygraph
• Must be in the Maryland area
Preferred Qualifications
• Experience leading technical initiatives and mentoring developers
• Knowledge of cryptographic algorithms or cybersecurity concepts
• Contributions to major open-source projects
• Experience with modeling, simulation, and analysis tools
• Experience with front-end UI/UX development
• Familiarity with network simulation tools or packet tracing utilities (e.g., Wireshark, Scapy)
• Experience with cloud-native platforms such as Kubernetes, AWS, or Azure
Location This position will be onsite in the Odenten/Severn/Annapolis Junction area in Maryland. Security and Citizenship Requirement The employee must have a TS/SCI with full-scope polygraph Benefits of Note We offer a robust benefits package to provide for your and your family's well-being, including:
• 401(k) retirement plan with 5% employer match and immediate vesting
• Fully paid medical insurance plans for you and your family
• Employer paid dental and vision plans for you and your family
• 5 weeks of PTO and 11 days of paid company holidays each year Application Instructions Only candidates applying directly to our posted job opening will be considered. We are not accepting unsolicited resumes from recruiters or employment agencies at this time. Equal Employment Opportunity ExistX is an Equal Opportunity Employer and does not discriminate in employment opportunities or practices based on race, ethnicity, national origin, ancestry, color, sex, gender identity or expression, sexual orientation, marital or parental status, pregnancy or childbirth, disability, age, religion, creed, genetic information, veteran status, or any other characteristic protected by applicable federal, state, or local law. We encourage and respect different viewpoints and experiences as being essential to the process of innovation. We strive to acquire, grow, and maintain a diverse and inclusive workplace that applies principles and standards equitably while supporting the needs and accommodations of the individual employee. Consistent with the Americans with Disabilities Act (ADA) and federal and state laws, it is the policy of ExistX. to provide reasonable accommodation when requested by a qualified applicant or employee with a disability unless such accommodation would cause an undue hardship. If you require reasonable accommodation in completing the employment application, interviewing, completing any pre-employment testing, or otherwise participating in the employee selection -process, please contact .