Senior Principal Software Engineer, Onsite (Marlborough)

Date Posted: 2026-07-25 Country: United States of America Location: US-MA-MARLBOROUGH-MA4 ~ 1001 Boston Post Rd ~ BLDG 4 Position Role Type: Onsite U.S. Citizen, U.S. Person, or Immigration Status Requirements: 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 Security Clearance Type: DoD Clearance: Secret Security Clearance Status: Active and existing security clearance required on day 1 At RTX, the world's largest aerospace and defense company, 185,000 great minds are united by purpose and inspired to make a difference solving the world’s most complex problems. With our three market leading businesses, world-class operations and investments in research and development, we offer capabilities and opportunity no one else can. Together, we push the boundaries of known science and find new ways to connect and protect our world. Collins Aerospace is a leader in technologically advanced, intelligent solutions that help redefine the aerospace and defense industry. With a comprehensive portfolio and deep technical expertise, we help customers meet the demands of the global market. Join us and help shape the future of aerospace and defense. Raytheon Company, Managed by Collins Aerospace Collins Aerospace, an RTX company, is a leader in engineering and proposal teams to successfully execute programs and prepare responsive proposals aimed at making the world a safer place. Come support those who provide us with all the freedoms we enjoy. Our commitment to providing an environment that supports innovation, teamwork, and growth opportunities are primary reasons engineers come to work at RTX. The Strategic Communication Software (SW) Engineering Department has an opportunity for a talented Sr. Principal Software Engineer to join our team.

What You Will Do

• Participate on collaborative, cross-disciplined integrated product teams, often employing agile software development techniques
• Responsible for the full lifecycle of product development, from architecture and design, through integration, test, and field support
• Work and learn the highest software engineering process maturity level as recognized by the Software Engineering Institute

Qualifications

• Experience in Software Engineering to include experience working various phases of the software development lifecycle
• Prior experience in a technical or team leadership role, such as SW Architect, SW Lead etc
• Experience with Software Development Using C++
• Experience with real-time operating systems (RTOS), embedded programming, processor/board architecture and design
• Working knowledge of Linux, VxWorks or other Real time operating systems
• Applied experience in Unified Modeling Language (UML) and Object-Oriented Analysis and Design (OOA/D)
• Experience working in a collaborative team environment that requires communication with other engineering disciplines, Program, and external stakeholders
• Mentoring experience with junior engineers
• 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
• Typically requires a degree in Science, Technology, Engineering or Mathematics (STEM) and minimum 10 years prior relevant experience or an Advanced Degree in a related field and minimum 7 years of experience

Preferred Qualifications

• Understanding of standard system engineering design artifacts such as Use Cases and SysML diagrams
• Experience with Agile lifecycle process including Scrum, Continuous Integration, and Test-Driven Development Methodologies
• Experience with DevOps, Jenkins and automated testing
• Experience with Model Driven Development
• Experience with software integration on custom hardware FPGA interfaces (memory mapped and SW/FW messaging) experience
• Working experience with Microservice Architectures and Containerized Applications Versal (ARM assembly) knowledge
• Performance optimization experience
• CORBA experience
• Scripting language (e.g. Python)

Benefits

• Medical, dental, and vision insurance
• Three weeks of vacation for newly hired employees
• Generous 401(k) plan that includes employer matching funds and separate employer retirement contribution, including a Lifetime Income Strategy option
• Tuition reimbursement program
• Student Loan Repayment Program
• Life insurance and disability coverage
• Optional coverages you can buy pet insurance, home and auto insurance, additional life and accident insurance, critical illness insurance, group legal, ID theft protection
• Birth, adoption, parental leave benefits Ovia Health, fertility, and family planning Adoption Assistance
• Autism Benefit
• Employee Assistance Plan, including up to 10 free counseling sessions
• Healthy You Incentives, wellness rewards program
• Doctor on Demand, virtual doctor visits
• Bright Horizons, child and elder care services
• Teladoc Medical Experts, second opinion program
• Eligible for relocation And more!

The salary range for this role is 132,400 USD - 251,600 USD. The salary range provided is a good faith estimate representative of all experience levels. RTX considers several factors when extending an offer, including but not limited to, the role, function and associated responsibilities, a candidate’s work experience, location, education/training, and key skills. Hired applicants may be eligible for benefits, including but not limited to, medical, dental, vision, life insurance, short-term disability, long-term disability, 401(k) match, flexible spending accounts, flexible work schedules, employee assistance program, Employee Scholar Program, parental leave, paid time off, and holidays. Specific benefits are dependent upon the specific business unit as well as whether or not the position is covered by a collective-bargaining agreement. Hired applicants may be eligible for annual short-term and/or long-term incentive compensation programs depending on the level of the position and whether or not it is covered by a collective-bargaining agreement. Payments under these annual programs are not guaranteed and are dependent upon a variety of factors including, but not limited to, individual performance, business unit performance, and/or the company’s performance. This role is a U.S.-based role. If the successful candidate resides in a U.S. territory, the appropriate pay structure and benefits will apply. RTX anticipates the application window closing approximately 40 days from the date the notice was posted. However, factors such as candidate flow and business necessity may require RTX to shorten or extend the application window.

Onsite: Employees who are working in Onsite roles will work primarily onsite. This includes all production and maintenance employees, as they are essential to the development of our products. At Collins, the paths we pave together lead to limitless possibility. And the bonds we form – with our customers and with each other -- propel us all higher, again and again.

RTX is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability or veteran status, or any other applicable state or federal protected class. RTX provides affirmative action in employment for qualified Individuals with a Disability and Protected Veterans in compliance with Section 503 of the Rehabilitation Act and the Vietnam Era Veterans’ Readjustment Assistance Act.

RTX is an aerospace and defense company that provides advanced systems and services for commercial, military and government customers worldwide. It comprises three industry-leading businesses – Collins Aerospace, Pratt & Whitney, and Raytheon. Its 195,000 employees enable the company to operate at the edge of known science as they imagine and deliver solutions that push the boundaries in quantum physics, electric propulsion, directed energy, hypersonics, avionics and cybersecurity. The company, formed in 2020 through the combination of Raytheon Company and the United Technologies Corporation aerospace businesses, is headquartered in Arlington, Virginia.