> Markdown version of [/jobs/ext/1218994-principal-software-engineer](https://www.wearedevelopers.com/jobs/ext/1218994-principal-software-engineer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Principal Software Engineer - **Company:** RTX - **Location:** Concord, NH, United States - **Experience:** Expert - **Salary:** $107,500.0 - $204,500.0 - **Contract:** Contract - **Skills:** Java (Programming Language), Agile Methodology, Software Applications, Bash Shell, C++ (Programming Language), IBM Rational ClearCase, Code Review, Data Structures, Software Debugging, Distributed Systems, Memory Management, Network Service, Object-Oriented Software Development, Performance Tuning, Scrum Methodology, Real-Time Operating Systems, Software Tools, Shell Script, Software Engineering, Systems Architecture, Systems Integration, VxWorks, Multithreading, Enterprise Software Applications, Real Time Systems, Git, Solid Principles, Software Version Control - **Published:** July 9, 2026 - **Apply:** https://globalhr.wd5.myworkdayjobs.com/REC_RTX_Ext_Gateway/job/US-MA-TEWKSBURY-TB3--50-Apple-Hill-Dr--CONCORD-BLDG-Tewksbury-Tb3-300-Concord/Principal-Software-Engineer_01858385 ## About the Role Active and transferable U.S. government issued security clearance is required prior to start date. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance, Ability to obtain INTERIM U.S. government issued security clearance is required prior to start date, * Typically requires a bachelor's in science, Technology, Engineering, or Mathematics (STEM) and a minimum of 8 years of experience. * Experience in developing complex systems and applications using C/C++, Java or other object-oriented programming language. * Experience in embedded systems, real-time systems, or large-scale applications. * Experience in a Unix/Linux operating system. Qualifications We Prefer * Active Secret security clearance. * Experience with multithreading, memory management, or performance optimization in complex environments. * Experience with data structures, algorithms, and software design principles, particularly in high-concurrency and distributed systems. * Experience with Network Communication Protocols, Shell Scripting (tcsh, csh, bash), software development tools like Git/Clearcase, software debuggers, and using embedded RTOSs (e.g. VxWorks, Integrity). * Experience with with version control systems (e.g., Git). * Experience with software development methodologies (Agile, Scrum, etc.). ## Description We are seeking a skilled and detail-oriented Principal Software Development Engineer with a focus on developing complex systems in C/C++ as part of our Patriot Software Team in Tewksbury, Massachusetts. The ideal candidate will have a passion for creating high-performance applications and will be involved in all stages of the software development lifecycle. Patriot is the world's pre-eminent air defense system, and we are currently developing software in support of new system capabilities. In this role, you will work closely with software developers, system architects, and product leads to ensure that the solutions we deliver meet our customers' requirements. You'll have the opportunity to work in a dynamic, fast-paced environment where your contributions will have a direct impact on the success of our products around the world. The position works in a SCIF environment with an optional 9/80 schedule accommodate work/life balance practices. What You Will Do * Design, develop, and maintain software applications using C and C++ for complex systems and applications. * Collaborate with cross-functional teams to define, design, and implement new features, ensuring system integration and scalability. * Troubleshoot, debug, and optimize existing code for performance and efficiency in complex environments. * Write and maintain comprehensive documentation for software applications, including system architecture and design specifications. * Participate in code reviews and ensure adherence to coding standards and best practices. * Stay current with industry trends and advancements in C/C++ technologies, especially in relation to complex systems. * Light travel and off hours testing (2nd or 3rd shift) may occasionally be required. * This position requires exclusive onsite presence. ## Related Videos - [Navigating the Corporate Jungle: Life as a Developer in a large Company](https://www.wearedevelopers.com/videos/621-navigating-the-corporate-jungle-life-as-a-developer-in-a-large-company) - [Old tools, new tricks](https://www.wearedevelopers.com/videos/1916-old-tools-new-tricks) - [How a Small Team Shrank a Microsoft Monorepo by 94%](https://www.wearedevelopers.com/videos/1236-how-a-small-team-shrank-a-microsoft-monorepo-by-94) - [Grappling With Clunky Old Software? 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