Senior Application Developer

SOS International LLC; United States; On-site; USD 140,000 - 155,000; Full time

Job summary

SOS International LLC is seeking a Senior Application Developer to join our on-site team at Fort Belvoir, VA, to design, develop, and maintain complex software applications. The role emphasizes .NET Core proficiency, system integration, and mentorship of junior developers within the ITCD program.

The ideal candidate will have a Top Secret clearance (or ability to obtain), 5+ years in a supervisory development role, experience with GOTS applications, and strong skills in C#, JavaScript, REST

Qualifications

• Active Top Secret clearance or ability to obtain Top Secret (SCI desirable)
• 5+ years of technical supervisory experience in a software development environment
• Experience with GOTS applications such as ARMIS, AAO, ACOTD, FACTS, MDR, or ADAMS
• Strong programming skills in C#, JavaScript, .NET or similar; cloud platforms and services
• Proficiency with REST APIs, microservices, and application integration patterns
• Experience with CI/CD pipelines, version control, and automated testing
• Excellent communication and stakeholder engagement abilities
• Ability to lead multiple concurrent projects and mentor junior developers

Responsibilities

• Design, develop, test, and maintain high-performance software applications
• Lead architecture and design of components and integrations
• Collaborate with product management, QA, and DevOps teams
• Mentor junior developers and contribute to knowledge sharing
• Maintain documentation and ensure adherence to standards
• Support project managers with scheduling and execution
• Monitor application performance and optimize for efficiency
• Stay updated with emerging technologies and recommend solutions

Skills

.NET

C#

JavaScript

REST APIs

Microservices

AWS

Azure

GCP

CI/CD

Cloud

Education

Bachelor’s or postgraduate degree in engineering/science/technical/business management

Tools

Microsoft SQL Server

Git

CI/CD pipelines

Job description

Senior Application Developer

• Full-time
• Clearance Requirement: Top Secret
• Compensation: USD 140,000 - USD 155,000 - yearly

Company Description

Founded in 1989, SOSi is among the largest private, founder-owned technology and services integrators in the defense and government services industry. We deliver tailored solutions, tested leadership, and trusted results to enable national security missions worldwide.

Job Description

Overview:

SOSi is seeking a highly qualified Senior Application Developer to join our team on site in Fort Belvoir, VA, in support of our government customer. In this role, the Senior Application Developer will serve as a technical expert responsible for the design, development, integration, and maintenance of complex software applications. The position requires a strong proficiency in .NET Core and extensive experience supporting the operation, enhancement, and modernization of the ITCD (Information Technology and Compliance Directorate) family of applications. The ideal candidate excels in system integration, collaborates effectively across teams, delivers high‑quality solutions, and provides mentorship to junior developers. This role is best suited for someone who is proactive, detail‑oriented, and committed to building reliable and scalable systems.

Essential Job Duties:

• Design, develop, test, and maintain high‑performance software applications.
• Analyze business requirements and translate them into technical specifications.
• Lead the architecture and design of application components and integrations.
• Review code for accuracy, quality, and adherence to best practices.
• Troubleshoot and resolve complex technical issues across the application stack.
• Collaborate with cross‑functional teams, including product managers, QA, and DevOps.
• Contribute to process improvements, automation, and development standards.
• Mentor junior developers and support team knowledge sharing.
• Stay current with emerging technologies and recommend solutions when appropriate.
• Support the project manager in overseeing project operation, planning, and execution.
• Formulate objectives and levels of effort through research and fact-finding with customer representatives and project managers.
• Be responsible for the software development life cycle from planning to implementation to testing and documenting, to deployment and maintenance.
• Assist the project manager and client in developing a schedule/timeframe for each project to ensure each one is executed efficiently and in a timely manner.
• Create and maintain complete and accurate documentation on all supported applications.
• Oversee technical issues related to the operation, maintenance, and modification of GOTS application.
• Work with customer stakeholders to design or customize software with a focus on optimizing operational efficiency.
• Apply knowledge of hardware and/or software engineering principles.
• Design and/or customize software for client use to optimize operational efficiencies.
• Monitor application performance and perform application changes to optimize performance.
• Analyze and design GOTS applications and systems with a focus on improving functionality and stakeholder usability.
• Provide evaluations and recommendations of GOTS applications and systems to provide solutions to complex technical challenges.
• Follow all applicable agency policies, procedures, and regulations.
• Provide technical guidance to lower-level developers and engineers.

Qualifications

• Bachelor’s degree or postgraduate degree in engineering, scientific, technical, or business management disciplines from an accredited college or university.
• A minimum of 5 years of technical supervisory experience in an application/software development environment.
• An active in scope Top Secret security clearance, or Secret with the ability to obtain a Top Secret.
• Experience with GOTS applications such as ARMIS, AAO, ACOTD, FACTS, MDR, or ADAMS.
• Experience with Microsoft SQL and the .NET framework.
• Experience with Configuration Management processes including Change Control Boards (CCB).
• Ability to schedule, track, and perform across multiple concurrent projects.
• Must have demonstrated the ability to communicate with a variety of stakeholders in multiple formats.
• Must possess baseline and computing environment certifications for IAT-II IAW DoD 8570.01-M (CCNA-Security, CySA+, GICSP, GSEC, Security+, CND, or SSCP).
• 5–8+ years of professional experience in software or application development.
• Strong proficiency in modern programming languages and frameworks (such as C#, JavaScript, .NET, or similar).
• Hands-on experience with cloud platforms and services (AWS, Azure, or GCP).
• Proficiency with REST APIs, microservices, and application integration patterns.
• Solid understanding of relational and NoSQL databases.
• Experience with CI/CD pipelines, version control systems, and automated testing.
• Strong analytical, problem‑solving, and communication skills.
• Ability to work independently while supporting team goals.

Additional Information

Work Environment:

• Normal office conditions.
• Core hours of operation are Monday through Friday, 0600 – 1700.
• On government site within Ft. Belvoir, VA.

Working at SOSi:

• All interested individuals will receive consideration and will not be discriminated against for any reason.