3Si · 1 week ago
Software Developer II (Mid-Level)
Ashburn,VA,US
Full-time
Onsite
Mid, Senior Level
5+ years exp3Si is a global leader in innovative security technology, helping businesses and law enforcement prevent and respond to crime. The Mid-Level Software Developer is responsible for participating in technical development, testing, debugging, and implementation of enhancements to enterprise-level applications.
GPSPhysical SecuritySecurity
Responsibilities
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
Qualification
Required
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
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
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
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
Benefits
Competitive benefits
Hybrid, flexible work culture
Company
3Si
Redefined Actionable Intelligence: With a fresh new look and a revolutionary purpose and mission, we are positioned to better serve our clients, partners, law enforcement, and communities with our cutting-edge technologies and real-world experience to deliver redefined actionable intelligence via an integrated platform that significantly impacts the bottom line – and, more importantly, lives.
201-500 employees
H1B Sponsorship
3Si has a track record of offering H1B sponsorships. Please note that this does not
guarantee sponsorship for this specific role. Below presents additional info for your
reference. (Data Powered by US Department of Labor)
Distribution of Different Job Fields Receiving Sponsorship
Represents job field similar to this job
Trends of Total Sponsorships
2024 (1)
2021 (1)
Funding
Current Stage
Growth StageTotal Funding
$13MKey Investors
American Capital
2017-06-20Acquired
2002-07-29Series Unknown· $13M
Leadership Team
Matt Kushner
Chief Executive Officer
Todd Leggett
CEO
Recent News
2025-09-30
Morningstar.com
2025-09-12
Company data provided by crunchbase