Sr. Full Stack Engineer

The Sr. Full Stack Engineer is a key contributor within the IT organization responsible for the architecture, development, deployment, and maintenance of full-stack applications that power ADDMAN's business operations. This role will play a pivotal part in building out the development department at ADDMAN, designing and delivering distributed systems end-to-end-from backend service workers and middleware through business logic, routing, and user-facing interfaces.

This role leads the design, development, and operation of full-stack applications built on a modern technology stack:
React (with Vite) on the frontend, C# and Node.js (Fastify) on the server side, and a backend infrastructure spanning Postgre

SQL, SQL Server, Redis, and Mongo

DB, with business functions deployed in C#. The Sr. Full Stack Engineer is expected to own solutions end-to-end-including architecture, coding, data modeling, deployment, monitoring, and ongoing maintenance-while producing the documentation and project roadmaps needed to scale the team.

Reporting directly to the VP of IT, this role bridges software architecture, application engineering, and data engineering. The ideal candidate is a self-starter who thrives in a fast-paced environment with evolving priorities, and plays a core part in delivering the digital backbone for "One Company."

This position is subject to the International Traffic in Arms Regulations (ITAR) which requires U.S. citizen status. This is a fully remote position, with some travel to ADDMAN sites required as needed.

Requirements

ESSENTIAL JOB FUNCTIONS:

• Architect, develop, and maintain full-stack applications end-to-end, including frontend (React/Vite), backend services (C# and Node.js/Fastify), middleware for business logic and routing, and backend data infrastructure (Postgre
  
  SQL, SQL Server, Redis, Mongo
  
  DB).
• Design and implement distributed systems, including backend service workers, business-logic middleware, API routing layers, and user-facing interfaces that operate reliably at scale.
• Develop, deploy, and maintain business functions in C#, as well as server-side applications using C# and Node.js (Fastify), ensuring performance, security, and maintainability across environments.
• Model, query, and optimize data across relational and non-relational stores-primarily Postgre
  
  SQL and SQL Server, with Redis for caching and Mongo
  
  DB for document workloads-and perform data analysis to support data-driven decision making.
• Own the full software development lifecycle (SDLC) using standard patterns-requirements, design, development, testing, deployment, and maintenance-including CI/CD, version control, code reviews, and release management.
• Produce and maintain clear technical documentation, including architecture diagrams, API references, deployment runbooks, and a living project roadmap that aligns engineering work with business priorities.
• Partner with stakeholders across the business to translate requirements into reliable, maintainable software-delivering features iteratively in a fast-paced environment with changing demands and shifting priorities.
• Monitor, troubleshoot, and continuously improve application performance, reliability, and security across production environments, and mentor other engineers as the development department grows.
• Help shape the long-term engineering and application strategy in partnership with the VP of IT. Other duties as needed by the company and departments.

SKILL REQUIREMENTS:

• Expert-level proficiency in C# and Node.js, including hands-on experience building production-grade services, APIs, and business logic.
• Strong frontend development skills with React and Vite, including component architecture, state management, and performance optimization.
• Demonstrated experience architecting distributed systems, including service workers, middleware for business logic and routing, and full-stack applications delivered end-to-end.
• Strong data analysis skills with hands-on experience across multiple databases-primarily Postgre
  
  SQL and SQL Server-and working familiarity with Redis and Mongo
  
  DB.
• Self-starter who is comfortable working in a fast-paced environment with changing demands; able to…