Senior Fullstack Software Engineer Jobs in Chantilly, VA

The Work

The .NET Full Stack Developer, Senior, is responsible for the design, development, testing, and management of complex application development efforts in support of enterprise IT environments. This role encompasses programmatic integration of third‑party components, introduction of new custom capabilities, modification and enhancement of existing code, process improvement recommendations, and automation of operations and maintenance tasks.

This role develops and implements technical solutions to design, build, and deploy applications under the direction of lead architects, including support for large‑scale data processing, computationally intensive statistical modeling, and advanced analytics. The position participates in all phases of the software development life cycle (SDLC), including planning, requirements analysis, development, testing, deployment, and quality assurance.

This position aligns with Cayuse’s core values of Innovation, Excellence, Collaboration, Adaptability, and Integrity by fostering technical solutions that meet customer needs, promoting teamwork, and prioritizing quality in deliverables.

Key Responsibilities

• Design, develop, test, and manage application development projects in support of enterprise IT infrastructure and services.
• Integrate third‑party components programmatically and introduce new custom capabilities to meet evolving functional and non‑functional requirements.
• Maintain and enhance existing applications by modifying code, improving performance, and refactoring for scalability, reliability, and maintainability.
• Identify, recommend, and implement process improvements; design and develop automation for operations and maintenance tasks to increase efficiency and reduce manual effort.
• Translate functional and technical requirements into robust, scalable software designs under the direction and guidance of lead architects.
• Design and implement solutions for large‑scale data processing, computationally intensive statistical modeling, and advanced analytics workloads.
• Participate in all aspects of the SDLC, including backlog refinement, sprint planning, requirements analysis, design, development, unit and integration testing, deployment, and ongoing quality assurance.
• Conduct and contribute to technical project milestone reviews, code and architecture review sessions, and technical design walkthroughs.
• Assist with effort and resource estimation for development tasks and projects; support planning and tracking of development activities.
• Apply and promote software development best practices, including secure coding standards, code reviews, automated testing, and continuous integration/continuous delivery (CI/CD).
• Prepare and maintain technical documentation (design specifications, interface control documents, deployment guides, and user/operations manuals).
• Collaborate effectively with cross‑functional teams including architects, business analysts, data engineers, testers, and operations staff to deliver high‑quality solutions.
• Mentor and provide knowledge transfer to junior developers and other team members through code reviews, pair programming, and technical presentations.
• Other duties as assigned.

Qualifications – Here’s What You Need

• Bachelor’s degree in Information Technology, Computer Science, Computer Engineering, or a related field.
• Minimum of 8 years of professional software development experience.
• Demonstrated experience designing, developing, testing, and managing enterprise applications.
• Hands‑on experience with programmatic integration of third‑party components, APIs, and services.
• Proficiency in modifying and extending existing codebases, including troubleshooting, performance tuning, and refactoring.
• Proven ability to identify, recommend, and implement process improvements and automation solutions for operational workflows.
• Experience working with large‑scale data processing, statistical modeling, or advanced analytics (e.g., ETL pipelines, distributed processing frameworks, or analytical computing).
• Strong understanding of the full software development life cycle, including requirements analysis, design, development, testing, deployment, and maintenance.
• Solid problem‑solving and analytical skills, with the ability to diagnose complex technical issues and propose effective solutions.
• Strong verbal and written communication skills, with the ability to collaborate across technical and non‑technical stakeholders.
• Demonstrated ability to work both independently and as part of a collaborative, agile team environment.
• Top Secret Clearance is required.
• Must be able to pass a background check. May require additional background checks as required by projects and/or clients at any time during employment.

Minimum Skills Required:

• Proficient in Microsoft and Adobe toolsets, including Excel, Word, PowerPoint, Acrobat, etc.
• Strong understanding of software development best practices.
• Ability to recommend and implement software upgrades.
• Experience in software maintenance and testing to ensure continued functionality.
• Excellent problem-solving and debugging skills.
• Strong communication and collaboration skills.
• Knowledge of database management and integration.
• Understanding of web security best practices.
• Ability to document processes and code for future maintenance and upgrades.

Preferred Qualifications:

• Five‑year degree (e.g., combined bachelor’s/master’s program) in Information Technology, Computer Science, or a related discipline, or equivalent combination of education and experience.
• Prior experience working in close collaboration with lead or enterprise architects on system and application design.
• Familiarity with conducting and contributing to technical project milestone reviews, architecture review boards, and formal design reviews.
• Experience with effort and resource estimation for software development tasks and projects.
• Strong knowledge of and adherence to modern development best practices (e.g., design patterns, SOLID principles, secure coding, DevSecOps, CI/CD, automated testing frameworks).
• Experience mentoring and coaching junior developers, including conducting code reviews and delivering technical training or knowledge‑sharing sessions.
• Exposure to or experience with advanced analytics platforms, big data technologies, or high‑performance computing environments (as applicable to your organization’s tech stack).

Our Commitment to you / overview of benefits

• Medical, Dental and Vision Insurance; Wellness Program.
• Flexible Spending Accounts (Healthcare, Dependent Care, Commuter).
• Short-Term and Long-Term Disability options.
• Basic Life and AD&D Insurance (Company Provided).
• Voluntary Life and AD&D options.
• 401(k) Retirement Savings Plan with matching after one year.
• Paid Time Off.

Reports to: Program Manager

Working Conditions

• Professional office environment.
• Ability to work on site in Washington, DC.
• Must be physically and mentally able to perform duties extended periods of time.
• Ability to use a computer and other office productivity tools with sufficient speed to meet the demands of this position.
• Must be able to establish a productive and professional workspace.
• Must be able to sit for long periods of time looking at computer screen.
• May be asked to work a flexible schedule which may include holidays.
• May be asked to travel for business or professional development purposes.
• May be asked to work hours outside of normal business hours.

Other Duties: Please note this job description is not designed to cover or contain a comprehensive list of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities, and activities may change at any time with or without notice.

Cayuse is an Equal Opportunity Employer. All employment decisions are based on merit, qualifications, skills, and abilities. All qualified applicants will receive consideration for employment in accordance with any applicable federal, state, or local law.