Software Engineer III

Location: Colorado Springs, CO

Work Arrangement: Onsite

Salary Range: $93,000–$140,000 annually

Security Clearance: Active Secret Clearance is Required

Recruitment Partner Notice

This position is being recruited and advertised by The O'Neil Group Company, LLC on behalf of ONE Dev, LLC. Applications will be submitted through The O'Neil Group Company, LLC; however, the selected candidate will be employed directly by ONE Dev directly and will work onsite at a Colorado Springs location.

About ONE Dev

ONE Dev is a women-owned small business headquartered in Colorado Springs, home to five military installations and a robust ecosystem of aerospace and defense organizations, innovative startups, entrepreneurs, government partners, and academic institutions.

ONE Dev's Engineering Services team combines decades of aerospace and Command and Control (C2) mission domain experience with modern engineering practices that keep missions ready, resilient, and ahead of the threat.

Position Summary

ONE Dev is seeking an experienced Software Engineer III professional responsible for designing, developing, integrating, and delivering complex software applications and systems supporting demanding technical and operational requirements. The individual applies advanced software engineering principles, extensive programming experience, and strong analytical capabilities to develop scalable, secure, and high-performance software solutions.

Responsibilities include leading the design and implementation of complex software components, evaluating technical requirements, developing software architectures and interfaces, resolving challenging engineering issues, and ensuring compliance with established development standards and cybersecurity requirements. The Software Engineer III provides technical direction to junior engineers, conducts detailed code and design reviews, and contributes to the continuous improvement of software development processes.

In support of government and defense-related missions, the Software Engineer III may lead development efforts involving mission-critical command and control applications, modeling and simulation systems, data processing platforms, cloud-based environments, and software modernization initiatives. The position requires significant technical independence, demonstrated problem-solving capabilities, and the ability to coordinate engineering activities across multidisciplinary teams.

Required Qualifications

• \n
• Active Secret security clearance.\n
• Advanced proficiency in software development, system integration, software architecture, automated testing, Agile/DevSecOps methodologies, and secure software engineering practices\n
• Experience mentoring junior engineers, leading technical tasks, and contributing to software design decisions.\n
• Experience with cloud platforms, containerization, and modern deployment practices\n
• Strong technical communication, documentation, and teamwork skills\n
• Ability to obtain or maintain a U.S. Government security clearance when required by the assigned program\n
• Due to U.S. Government security clearance and classified-access requirements associated with this position, U.S. citizenship is required.\n

Preferred Qualifications

• \n
• Active Top Secret/SCI (TS/SCI) security clearance\n
• Experience with microservices architectures and distributed systems\n
• Familiarity with event-driven architectures and asynchronous processing\n
• Background in performance optimization and scalability\n
• Experience working on government, defense, or mission-critical systems\n
• Knowledge of security best practices and secure coding standards\n
• Contributions to open-source projects or technical communities\n