Senior Software Engineer

Twenty-Six Defense • Merrimack, NH

17h

About The Position

The Senior Software Engineer supports the design, development, integration, and sustainment of software for Active Protection Systems (APS) programs in a classified environment. The role spans the software lifecycle, including requirements analysis, software design, C/C++ implementation, hardware and system integration, and verification and validation. The engineer works with internal teams and external customers to refine requirements, develop prototypes, and deliver mission-critical APS capabilities.

The position contributes to APS product development, testing, and validation; develops and maintains applications and embedded software; and supports testing, troubleshooting, documentation, and system integration. It collaborates with systems, hardware, electrical, and test engineering disciplines. Required travel is approximately 15%, including international travel.

Requirements

• Bachelor’s degree in Engineering, Computer Science, or a related technical field.
• Five or more years of related experience.
• Experience with C/C++ and Python software development.
• Must hold or be able to obtain a SECRET security clearance.
• Proficiency in software development processes, including requirements, design, implementation, and testing.
• Strong understanding of software development lifecycles and structured engineering processes.
• Solid understanding of interactions between software and hardware components.
• Strong written and verbal communication skills.
• Ability to work effectively in a classified environment while following security procedures.

Nice To Haves

• Experience in embedded, real-time, or hardware-adjacent software environments is preferred.
• Experience working in classified or defense environments is a plus.
• Experience supporting integrated hardware-software systems is beneficial.

Responsibilities

• Provide software engineering input to the APS product team through development, testing, and validation activities.
• Develop and maintain C/C++ applications and embedded software for new features, system upgrades, and end-of-life replacements.
• Support interpretation and implementation of internal and external customer application requirements.
• Review and become familiar with existing codebases, including subcontractor- or partner-developed modules.
• Write high-quality, maintainable source code within established deadlines.
• Perform unit and integration testing prior to release.
• Troubleshoot reported issues, identify root causes, and implement corrective actions.
• Identify, document, and propose solutions for software defects.
• Contribute to the development and execution of test plans, procedures, and verification reports for qualification and acceptance testing.
• Support laboratory testing on breadboards, mock-ups, and system integration test setups.
• Create and maintain task lists and engineering documentation.
• Assist with system integration, field testing, and system-level troubleshooting.
• Collaborate with systems, hardware, electrical, and test engineering disciplines.

Benefits

• Most locations offer a 9/80 schedule, providing every other Friday off.
• Competitive compensation and a 401(k) program.
• Medical, dental, vision, and disability coverage with qualified wellness discounts.
• Basic Life Insurance and additional Life and AD&D insurance are available.
• Flexible Vacation and PTO.
• Paid Parental Leave.
• Employee Referral Program.
• Voluntary benefits, including Long-Term Care, Legal, Identity Theft, and Pet Insurance.
• Voluntary Tricare Supplement available for military retirees.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior