Full Stack Developer

Eccalon, LLC is seeking a Full Stack Developer to build and ship production software for DoD, intelligence, and enterprise programs. The role owns end-to-end feature development across React and Next.js front ends, Node.js and Python APIs, AWS services, data stores, and LLM-powered capabilities while collaborating with cross-functional teams in a security-conscious environment.

Responsibilities

Design, develop, and maintain full-stack web applications from UI through API to data layer, with ownership of features across the entire delivery lifecycle

Build front-end architecture and UI components using React and Next.js; create reusable component libraries that support consistent UX across multiple products

Integrate LLM and AI capabilities into product features using the Anthropic API (Claude) and other model providers; apply prompt engineering, retrieval-augmented generation (RAG), and agentic workflow patterns to build intelligent, context-aware application experiences

Translate designs and wireframes into high-quality, accessible, responsive code; leverage AI-assisted development tools (e.g., Claude Code) to accelerate implementation without sacrificing quality or security

Develop and maintain back-end services and REST APIs using Node.js and Python; design for security, scalability, and compliance from the start

Integrate front-end applications with back-end APIs and AWS cloud services (Cognito, Lambda, API Gateway, DynamoDB, RDS/PostgreSQL); implement authentication flows including OAuth2/OIDC and JIT provisioning

Implement security and data protection measures aligned to NIST 800-171 and CMMC requirements; apply OWASP Top 10 mitigations and participate in code-level security reviews

Implement responsive, accessible UI designs (WCAG 2.1) that render consistently across devices and browsers

Write clean, well-tested, and well-documented code; contribute to and enforce engineering standards through trunk-based development and peer code review

Conduct thorough code reviews with a focus on security, maintainability, and AI-generated code validation; mentor junior engineers on best practices

Troubleshoot and debug complex issues across the full stack, including integration points with LLM APIs, cloud services, and third-party authentication providers

Design and manage relational and NoSQL data models across PostgreSQL, DynamoDB, and MongoDB; optimize queries and data access patterns for performance and cost

Apply structured prompt engineering techniques?chain-of-thought, few-shot examples, tool use, and system prompt design?to build reliable, production-ready LLM-powered features; evaluate and mitigate prompt injection, hallucination, and data leakage risks

Partner with UX/UI designers, product managers, and DevOps to deliver features end-to-end; translate program requirements into scalable technical solutions

Stay current on advancements in LLM/AI tooling, web frameworks, and cloud-native development; bring new techniques back to the team through demos, documentation, and knowledge sharing

Preferred

experience in a DoD, federal contracting, or regulated environment a plus

familiarity with NIST 800-171, CMMC, or FedRAMP requirements preferred

Experience building AI-powered features using RAG, vector databases (e.g., pgvector, Pinecone), or LLM orchestration frameworks (e.g., LangChain, LlamaIndex)

Familiarity with model context protocol (MCP) patterns and structured tool-use design for LLM-integrated applications

Experience with Azure services (Azure AD, GCC High) or AWS GovCloud in a DoD or federal contracting environment

Familiarity with TypeScript across both front-end and back-end (Node.js/Next.js) codebases

Experience with Playwright or Cypress for end-to-end testing of web applications

Background in UX/UI collaboration with Figma or similar design tooling

DoD Environment Experience

Federal Contracting Experience

Regulated Environment Experience

NIST SP 800-171

CMMC

FedRAMP

AI Feature Development

Retrieval-Augmented Generation

Vector Databases

pgvector

Pinecone

LLM Orchestration

LangChain

LlamaIndex

Model Context Protocol

Structured LLM Tool Use

Azure Services

Azure AD

GCC High

AWS GovCloud

End-to-End Testing

Cypress

UX/UI Collaboration

Figma

Company

Strategy, innovation, and technology services for defense and security.

Hanover, Maryland, USA

https://www.eccalon.com/

Founded in 2017

51-200 employees

Qualifications

Bachelor?s degree in Computer Science, or a related field (or equivalent work experience)

3+ years of experience as a Full Stack Developer shipping production web applications

Strong proficiency in HTML5, CSS3, JavaScript/TypeScript (ES6+), React, and Next.js; comfort building and documenting reusable component libraries

Proficiency in Node.js and Python for server-side development; experience with Express.js, Nest.js, and/or Next.js API routes

Hands-on experience integrating LLM APIs (Anthropic Claude, OpenAI, or similar) into production applications; demonstrated ability to write effective prompts, implement RAG pipelines, and build tool-use/agentic workflows

Experience with relational databases (PostgreSQL) and NoSQL databases (DynamoDB); comfort writing and optimizing queries and managing schema migrations

Solid understanding of RESTful API design, microservices architecture, and AWS services (API Gateway, Lambda, Cognito, S3, CloudFront)

Proficiency with Git and trunk-based development workflows; experience with GitHub or GitLab for PR-based collaboration

Working knowledge of CI/CD pipelines (GitLab CI/CD) and cloud deployment practices on AWS; familiarity with security-focused DevSecOps gates

Strong analytical and problem-solving skills; ability to work independently across multiple concurrent projects and communicate technical decisions clearly to non-technical stakeholders

Comfort working in a regulated, compliance-aware environment

Strong interpersonal and communication skills; proven ability to collaborate effectively across engineering, design, DevOps, and program management teams

Experience in a DoD, federal contracting, or regulated environment a plus

Familiarity with NIST 800-171, CMMC, or FedRAMP requirements preferred

Experience building AI-powered features using RAG, vector databases (e.g., pgvector, Pinecone), or LLM orchestration frameworks (e.g., LangChain, LlamaIndex)

Familiarity with model context protocol (MCP) patterns and structured tool-use design for LLM-integrated applications

Experience with Azure services (Azure AD, GCC High) or AWS GovCloud in a DoD or federal contracting environment

Familiarity with TypeScript across both front-end and back-end (Node.js/Next.js) codebases

Experience with Playwright or Cypress for end-to-end testing of web applications

Background in UX/UI collaboration with Figma or similar design tooling

Required skills

React, Next.js, Node.js, Python, TypeScript, LLM Application Integration, Prompt Engineering, Retrieval-Augmented Generation (RAG), PostgreSQL, DynamoDB, AWS, RESTful API Design

Preferred skills

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Experience

3+ years