Software Engineer

About Us

ExistX was founded in 2023 with the goal to combine cutting edge invention with practical implementation in the unique environments our customers demand to solve national security problems in the real world. 

Our team of software and systems engineers bring experience working with cutting-edge advancements in cryptography, cyber-physical systems, MBSE, and formal methods for both government and commercial applications. We leverage a unique suite of capabilities—incubated through our sister R&D firm, Galois, and other key research partnerships—to rapidly prototype and deliver impactful solutions to the warfighter.

                   ∃X.P(X):
                   For every problem (X), a solution exists (P).

The solution exists. Let’s build it together.

About This Role

We are seeking a mid-level Software Engineer with experience supporting Department of Defense (DoD) programs, specializing in flight control systems, autopilot software, or autonomous vehicle control. The ideal candidate will contribute to the design, implementation, testing, and certification of mission-critical software used in unmanned systems. This role involves close collaboration with systems engineers, other software engineers, program managers, and hardware engineers to develop high-reliability, safety-critical software in compliance with DoD and aerospace standards. You will join a small, growing team where every person’s contribution directly shape the Company’s growth and impact. You’ll collaborate with Program Management, Business Development, and senior executives as well as work alongside a group of world class engineers and researchers. We value curiosity, accountability, and collaboration.

You will join a small, growing team where every person’s contributions directly shape the Company’s growth and impact. You’ll collaborate with Human Resources, Marketing, Business Development as well as work with a group of world class engineers, researchers, and leaders. We value curiosity, accountability, and collaboration.

Responsibilities

These responsibilities are executed in close collaboration with the CEO, COO, and Engineering leadership.

Software Development & Integration

• Design, develop, and maintain embedded and/or real-time software for flight control systems, autopilots, and autonomous guidance functions


• Implement control algorithms, state estimation, sensor fusion, and actuator control logic


• Integrate software with avionics hardware, sensors, and communication subsystems


• Support hardware-in-the-loop (HIL), software-in-the-loop (SIL), and simulation-based testing

Program Execution

• Develop software in accordance with DoD acquisition and compliance requirements


• Participate in program reviews, design reviews, and milestone events (SRR, PDR, CDR)


• Support classified and unclassified program activities as required


• Collaborate with government stakeholders, prime contractors, and internal teams

Verification, Validation & Safety

• Develop unit tests, integration tests, and automated test frameworks


• Support verification and validation activities aligned with DO-178C, DO-331, MIL-STD-882, or similar standards


• Assist with requirements traceability, documentation, and configuration management


• Identify and mitigate software risks in safety-critical environments

Collaboration & Technical Growth

• Work closely with systems, controls, and test engineers to ensure end-to-end system performance


• Contribute to technical decisions, architecture discussions, and code reviews


• Mentor junior engineers and support continuous improvement of engineering practices

Qualifications

• Bachelor’s degree in Computer Science, Software Engineering, Aerospace Engineering, Electrical Engineering, or related field 3–7 years of professional software engineering experience


• Possess a current/or recent U.S. Government Security Clearance (Secret minimum; higher levels preferred) or the ability to obtain and maintain a U.S. government issued security clearance is required.
  
  
  
  • U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.
  
  
  
  


• Demonstrated experience supporting Department of Defense programs 


• Proficiency in C/C++ (required); experience with Python or MATLAB/Simulink strongly preferred


• Experience developing software for real-time or embedded systems


• Familiarity with flight controls, autopilot systems, or autonomous vehicle software


• Experience working in Linux-based development environments


• Understanding of software development lifecycle in regulated or safety-critical domains

Preferred

• Experience with UAS / UAV, aircraft, or spacecraft flight software


• Background in control theory, guidance & navigation, or state estimation (e.g., Kalman filters)


• Experience with PX4, ArduPilot, ROS/ROS2, or custom autopilot frameworks


• Familiarity with DO-178C, DO-331 (Model-Based Development), or similar standards


• Experience with HIL/SIL test systems, simulation tools, or digital twins


• Exposure to Model-Based Systems Engineering (MBSE) practices


• Active Top Secret clearance

Tools & Technologies

• Languages: C, C++, Python, MATLAB


• RTOS / Embedded Platforms: VxWorks, QNX, FreeRTOS, or equivalent


• Autonomy & Controls: Simulink, PX4, ArduPilot, custom GNC stacks


• DevOps / Tooling: Git, Jira, Jenkins, CMake, Docker


• Testing: HIL/SIL rigs, unit test frameworks, simulation environments

Success Criteria

• Reliable, high-quality flight control software delivered on schedule


• Strong collaboration across software, systems, and controls teams


• Clean, maintainable, and well-documented code


• Successful participation in program reviews and test campaigns


• Growing technical ownership of flight control or autonomy subsystems

General Attributes

• High attention to detail and time-management skills


• Highly organized and proactive, with excellent multitasking and prioritization skills


• Comfortable operating in a fast-paced, growth-focused environment with evolving priorities


• Collaborative mindset with a focus on clarity, accountability, and follow-through


• Curiosity for all things technology


• Strong interpersonal and communication skills

Location

ExistX is headquartered in Arlington, Virginia with additional locations in Dayton, Ohio and Portland, Oregon. We have some remote employees distributed across the U.S.

Position may require eligibility to work with cleared programs (active clearance not required, but preferred). Hybrid or onsite presence may be required depending on contract or security requirements. Occasional interaction with government customers, auditors, or security personnel will be required.

While we have a high preference for this role to be based in our Dayton, Ohio office, co-location in one of our core geographies, we will not be limited geographically for hiring this position.

Benefits

ExistX offers a highly competitive benefits program to support employees and their families, including:

• Competitive salaries


• Employer paid medical insurance plan


• Health Savings Account (HSA) with employer contributions


• Employer paid dental and vision insurance plans


• 401(k) retirement plan with employer match


• Flexible work location with a remote friendly culture


• Paid time off (25 days per year)