Full Stack Software Engineer MERN

Benefits:

• Health insurance
• Paid time off
• Vision insurance
• Competitive salary
• Dental insurance
• Flexible schedule

About FNS Systems LLC
At FNS Systems LLC, we are redefining how technology powers global business. We combine global expertise in AI, automation, and network transformation with a culture that values innovation, creativity, and impact.

About the Role
FNS Systems LLC is seeking a Full Stack Software Engineer to join our DevOps team. You will design, develop, and test application software for internal systems powering large-scale network automation. Collaborating with 5G Core Subject Matter Experts (SMEs), you will automate the deployment and upgrade of 5G Core Network Functions using containerized applications, Azure, CI/CD pipelines, and workflow automation engines.

Work Location
This opportunity requires an onsite presence twice a week at any of these hybrid locations:

• Middletown, NJ | Bedminster, NJ
• Dallas, TX | Plano, TX | Austin, TX
• Atlanta (Lenox), GA | Alpharetta, GA
• Bothell, WA | Redmond, WA

Key Responsibilities

• Design, develop, and maintain full-stack web applications using the MERN stack (MongoDB, Express.js, React, Node.js).
• Build scalable, secure RESTful APIs and responsive, reusable React UI components.
• Design and optimize MongoDB data models, indexes, and queries.
• Troubleshoot issues across the stack and manage Azure DevOps (ADO) CI/CD pipelines.
• Collaborate with cross-functional teams in an Agile environment to translate requirements into technical solutions.

Required Qualifications

• Proven production experience building web applications using the MERN stack.
• Strong JavaScript (ES6+) and practical working knowledge of TypeScript.
• Solid experience designing RESTful APIs and working with React hooks/component architecture.
• Hands-on experience with Azure DevOps (ADO) YAML pipelines for React/Node services.
• Strong understanding of authentication/authorization (JWT, OAuth/OIDC) and secure API patterns.
• Proficiency with Git, cloud fundamentals (Azure), and Agile methodologies.

Nice to Have

• Experience with Next.js or React state libraries (Redux, Zustand).
• Experience with Docker, containerized workflows, and Infra-as-Code.
• Experience with workflow/BPM engines (Camunda, BPMN) or orchestration platforms (Pronghorn).

Our Commitment to Diversity
Don’t meet every requirement? Studies show that many qualified candidates hesitate to apply unless they meet 100% of the criteria. If you meet around 50% and are excited about this role, we strongly encourage you to apply. We value potential and diverse perspectives.

Interview Integrity
AI tools like ChatGPT, Claude, and Cursor are part of daily life at FNS Systems, but interviews and assessments must be completed independently. Using AI tools, coaching platforms, or third-party assistance during the interview process without explicit permission will result in immediate disqualification.

Flexible work from home options available.