At 3Si, our mission is to make your world, safer. As a global leader in innovative security technology, we help businesses and law enforcement prevent and respond to crime through field-proven solutions and trusted partnerships. With over 100+ years of combined experience through our merged companies, our expertise drives measurable impact in communities worldwide.

We specialize in GPS tracking, video surveillance, and integrated response technologies that deter theft and accelerate criminal apprehension. Designed for retail, financial institutions, law enforcement, and more, our solutions combine cutting-edge tools with unmatched response capabilities. Through our exclusive DirectToDispatch™ technology, verified crime alerts are sent directly to law enforcement dispatch centers in real time—bypassing traditional third-party monitoring delays—to enable rapid, precise response when it matters most.

At 3Si, meaningful work makes a difference. We’re a purpose-driven team that values innovation, trust, and collaboration. From engineering to sales and support, every role contributes to our mission to protect communities and make the world safer. We offer a hybrid, flexible work culture, competitive benefits, and the chance to grow alongside a team of passionate, dedicated professionals.

Join us—and be part of something that matters. The Mid-Level Software Developer is responsible for participating in technical development, testing, debugging, and implementation of enhancements to enterprise-level applications. The developer is expected to work independently or collaboratively, with minimal oversight, contributing to the mission-critical success of our organization. Additionally, you may be tasked with writing Jira tickets, technical user guides, and supporting documentation.

• Participate in full software development lifecycle activities, including design, development, testing, debugging, and implementation
• Define and document functional requirements based on stakeholder input
• Design and develop scalable software solutions using C# and .NET
• Collaborate with other developers and cross-functional teams to ensure technical alignment with project goals
• Utilize development tools such as Visual Studio, Git, Jira, and 
• Work with technologies including REST/ServiceStack, WPF, Progress/Telerik UI Toolkit
• Support and maintain client and server utilizing REST and HTTPS protocols
• Perform other duties as needed to support the company’s mission and project requirements

Knowledge, Skills, and Abilities 

• Strong understanding of full-stack development practices
• Proficiency in C# and the .NET framework
• Experience with Windows Presentation Foundation (WPF)
• Knowledge of software development best practices and secure coding techniques
• Ability to work with RESTful APIs and HTTP network technologies
• Skilled in using Visual Studio, Git, and Jira
• Strong problem-solving and analytical abilities
• Effective communication and collaboration skills
• Ability to work independently or within a team environment

Qualifications

• Bachelor’s degree in Computer Science, Information Technology, Software Engineering, or a related technical field
• Equivalent professional experience may be considered in lieu of formal education
• Associate degree in a technical discipline combined with relevant experience and/or industry certifications may also be considered
• At least 5 years of related software development experience
• Minimum of 3 years of hands-on experience in C#/.NET development
• Experience with reusable C# library development and version-controlled environments

Additional Comments

• Position on-site in Ashburn, VA.
• Successful candidates must pass a comprehensive background investigation
• Pre-employment drug screening is required