Senior Software Engineer Jobs

Software EngineerLeidos is seeking a Software Engineer to be based in Gaithersburg, MD; Eagan, MN; or Egg Harbor, NJ. This position will support the United Kingdom National Airspace System Replacement Product Delivery Team - UK NASR PDT. This effort delivers enhanced capabilities to replace and modernize the current operational system supporting UK air traffic services. You will join a dynamic engineering team responsible for building and sustaining real-time, high-availability, safety-critical systems that directly support national airspace operations. Location This is a U.S.-based position that offers a balanced 50% hybrid schedule between 2-3 days in the office per week.What You'll DoDesign, develop, test, and maintain software for real-time, high-availability systemsLead software development activities independently and as part of a collaborative engineering teamAnalyze complex system requirements and translate them into efficient, maintainable software designsApply sound software engineering principles to ensure code is reliable, fault tolerant, reusable, and maintainableLead and mentor junior developers, influencing technical direction and development processesParticipate in Agile ceremonies including daily stand-ups, release planning, and sprint reviewsDevelop, tune, document, and deploy automation scripts across development, test, and production environmentsPromote code reuse, cross-program collaboration, and sustainable development practicesSupport system integration activities, including hardware and low-level communications interfacesRequired QualificationsBachelor's degree in Computer Science or related field with 4–8 years of relevant experience OR Master's degree with 2–6 years of relevant experienceAbility to obtain and maintain a Public Trust clearanceStrong object-oriented programming experienceProficiency in C and/or C++Experience developing real-time, multi-threaded, high-availability systemsExperience with Linux environments (Red Hat), virtual machines, and hypervisorsExperience with low-level communications protocols (TCP/IP, UDP, SCTP)Experience with hardware or complex system integrationFamiliarity with system maintenance and lifecycle conceptsExperience with source control and configuration management toolsStrong understanding of modern software development principles and best practicesAbility to plan and prioritize work effectively in a fast-paced environmentStrong verbal and written communication skillsDemonstrated ability to work independently and collaborativelyUS Citizenship RequiredPreferred QualificationsExperience with AdaExperience with test automation frameworksFamiliarity with AI coding tools and agents (Codex, Claude, or similar)Experience with Agentic and AI-assisted development workflows, including vibe codingFamiliarity with AI-enabled CI/CD, testing, code review, and DevSecOpsUnderstanding of AI-generated code validation, security, and responsible useWhy Leidos You'll contribute to software systems where reliability, performance, and precision are essential. This is an opportunity to work on mission-critical infrastructure supporting national airspace operations — collaborating with experienced engineers to modernize complex, real-world systems. If you are motivated by solving technically challenging problems in regulated, operational environments, we encourage you to apply. If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares.