Senior Software Engineer

Twenty-Six Defense; Merrimack (NH); On-site; USD 120,000 - 180,000; Full time

Benefits offered by this job

9/80 schedule

401(k) program

Medical, dental, vision coverage

Life Insurance

Paid Vacation & PTO

Parental Leave

Employee Referral Program

Voluntary Benefits

Tricare Supplement

Job summary

Twenty-Six Defense in Fort Worth, Texas, is seeking a Senior Software Engineer to design, develop, integrate, and sustain software for Active Protection Systems (APS) in a classified setting. You will contribute across the full software lifecycle, from requirements analysis to verification, collaborating with internal teams and customers on mission-critical capabilities.

The role emphasizes C/C++ and Python development, embedded software, and close coordination with systems, hardware, and test

Qualifications

• Bachelor’s degree in Engineering, CS, or related field.
• 5+ years of related experience.
• Experience with C/C++ and Python software development.
• Ability to obtain SECRET security clearance.
• Experience in embedded, real-time, or hardware-adjacent environments.
• Experience working in defense/classified environments is a plus.

Responsibilities

• Develop and maintain C/C++ applications and embedded software.
• Implement and test software across the full lifecycle.
• Collaborate with systems, hardware, and test engineering.
• Support lab testing and system integration.
• Document tasks and engineering activities.
• Assist with field tests and troubleshooting.

Skills

C/C++ development

Python development

Embedded software

Communication skills

Team collaboration

Education

Bachelor’s degree in Engineering, CS, or related field

Job description

Company Information

Twenty-Six Defense, headquartered in Fort Worth, Texas, is a leading provider of high-performance products, system solutions, and aftermarket support services focusing on the defense, homeland security, and commercial aviation markets. With facilities throughout the U.S., Twenty-Six Defense supports those who contribute to the national security of the United States. Twenty-Six Defense is wholly owned by Elbit Systems Ltd. (NASDAQ: ESLT and TASE: ESLT), a global high-technology company engaged in a wide range of programs for innovative defense and commercial applications.

Company Information

Twenty-Six Defense, headquartered in Fort Worth, Texas, is a leading provider of high-performance products, system solutions, and aftermarket support services focusing on the defense, homeland security, and commercial aviation markets. With facilities throughout the U.S., Twenty-Six Defense supports those who contribute to the national security of the United States. Twenty-Six Defense is wholly owned by Elbit Systems Ltd. (NASDAQ: ESLT and TASE: ESLT), a global high-technology company engaged in a wide range of programs for innovative defense and commercial applications.

Job Summary:

The Senior Software Engineer supports the design, development, integration, and sustainment of software for Active Protection Systems (APS) programs operating in a classified environment. This role contributes across the full software lifecycle, including requirements analysis, software design, implementation in C/C++, integration with hardware and systems, and verification/validation activities. The engineer collaborates with internal teams and external customers to support requirement refinement, prototype development, and delivery of mission‑critical APS capabilities.

Responsibilities And Tasks

• Provides software engineering input to the APS product team through development, testing, and validation activities.
• Develops and maintains C/C++ applications and embedded software for new features, system upgrades, and end‑of‑life replacements.
• Supports interpretation and implementation of internal and external customer application requirements.
• Reviews and becomes familiar with existing codebases, including subcontractor or partner‑developed modules.
• Writes high‑quality, maintainable source code within established deadlines.
• Performs unit testing and integration testing prior to release.
• Troubleshoots reported issues, identifying root causes and implementing corrective actions.
• Identifies, documents, and proposes solutions for software defects.
• Contributes to development and execution of test plans, procedures, and verification reports for qualification and acceptance testing.
• Supports laboratory testing on breadboards, mock‑ups, and system integration test setups.
• Creates and maintains task lists and engineering documentation.
• Assists with system integration, field testing, and system‑level troubleshooting.
• Collaborates closely with systems, hardware, electrical, and test engineering disciplines.

Education, Experience, License, Or Certification

• Bachelor’s degree in Engineering, Computer Science, or related technical field
• 5 or more years of related experience
• Experience with C/C++ and Python software development
• Candidate must hold or be able to obtain a SECRET security clearance
• Experience in embedded, real‑time, or hardware‑adjacent software environments preferred
• Experience working in classified or defense environments is a plus
• Experience supporting integrated hardware‑software systems beneficial

Skills And Abilities

• Proficient in software development processes including requirements, design, implementation, and test.
• 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 following security procedures.

Travel/Physical Requirements

• Required (approximately 15%), including international travel.

Here Are Some Of The Great Benefits We Offer

• Most locations offer a 9/80 schedule, providing every other Friday off
• Competitive compensation & 401(k) program to plan for your future
• Robust medical, dental, vision, & disability coverage with qualified wellness discounts
• Basic Life Insurance and Additional Life & AD&D Insurances are available
• Flexible Vacation & PTO
• Paid Parental Leave
• Generous Employee Referral Program
• Voluntary Benefits Available: Long-Term Care, Legal, Identity Theft, Pet Insurance, and more
• Voluntary Tricare Supplement available for military retirees

This job description does not list all the duties of the job. You may be asked by your supervisors or managers to perform other duties. The employer has the right to revise this job description at any time. The job description is not an employment contract. Reasonable accommodations may be made to enable individuals with disabilities to perform the essential functions of this position. Twenty‑Six Defense is an equal opportunity employer as to all protected groups, including protected veterans and individuals with disabilities.

• For Virginia-based positions only* In accordance with Virginia DOL requirements, the listed salary range reflects the anticipated base pay range for this role. Actual compensation will be determined based on factors including skills, experience, education, certifications, business needs, internal equity, and geographic location. Compensation may vary in different locations based on market conditions and cost-of-labor considerations.