Fullstack Engineer

Quantum Technologies. LLC; Sunnyvale, Northern (CA, KY); Hybrid; USD 120,000 - 160,000; Full time

Job summary

Quantum Technologies LLC seeks a highly skilled Full-Stack Engineer to build production-grade web applications and AI-powered agents using LangChain and LangGraph. You will design, develop, and maintain React-based frontends with Python backends, and implement scalable APIs and intelligent workflows.

The role emphasizes integrating LLMs, memory, tool-calling, and multi-step reasoning, along with RAG-based solutions and secure production practices.

Qualifications

• Proven experience with React (hooks, components, state) and Python (FastAPI/Flask/Django).
• Solid understanding of full-stack architecture, REST APIs, and backend development.
• Hands-on experience with LangChain for LLM app development.
• Hands-on experience with LangGraph for building/orchestrating AI agents.

Responsibilities

• Design, develop, and maintain full-stack web applications using React frontend and Python backend.
• Build scalable, secure, production-ready APIs and services.
• Implement AI agents and intelligent workflows using LangChain and LangGraph.
• Integrate LLMs into applications including tool-calling, memory, and multi-step reasoning.
• Design and implement RAG-based solutions using embeddings and vector databases.
• Orchestrate agent state, control flow, and execution using LangGraph.
• Ensure code quality through testing, reviews, and best practices.

Skills

React

Python

Full-stack architecture

REST APIs

LangChain

LangGraph

Git

LLMs integration

RAG embeddings

Tools

FastAPI/Flask/Django

Job description

We are looking for a highly skilledFull-Stack Engineerwho can build and maintainproduction-grade web applicationswhile also designing and implementingAI-powered agentsusingLangChain and LangGraph.

Responsibilities

• Design, develop, and maintainfull-stack web applicationsusingReact (frontend)andPython (backend)
• Build scalable, secure, and production-readyAPIs and backend services
• ImplementAI agents and intelligent workflowsusingLangChain and LangGraph
• IntegrateLLMsinto applications, including tool-calling, memory, and multi-step reasoning
• Design and implementRAG-based solutionsusing embeddings and vector databases
• Orchestrate agent state, control flow, and execution using LangGraph
• Ensure code quality throughtesting, code reviews, and best engineering practices

Required Skills

• Strong experience inReact(modern hooks, component design, state management) andPython(FastAPI / Flask / Django)
• Solid understanding offull-stack architecture, REST APIs, and backend development
• Hands-on experience withLangChainfor LLM application development
• Hands-on experience withLangGraphfor building and orchestrating AI agents
• Knowledge ofRAG architectures, embeddings, and vector databases
• Proficiency withGit, version control, and collaborative development workflows

QUANTUM TECHNOLOGIES LLC is an equal opportunity employer inclusive of female, minority, disability and veterans, (M/F/D/V). Hiring, promotion, transfer, compensation, benefits, discipline, termination and all other employment decisions are made without regard to race, color, religion, sex, sexual orientation, gender identity, age, disability, national origin, citizenship/immigration status, veteran status or any other protected status. QUANTUM TECHNOLOGIES LLC will not make any posting or employment decision that does not comply with applicable laws relating to labor and employment, equal opportunity, employment eligibility requirements or related matters. Nor will QUANTUM TECHNOLOGIES LLC require in a posting or otherwise U.S. citizenship or lawful permanent residency in the U.S. as a condition of employment except as necessary to comply with law, regulation, executive order, or federal, state, or local government contract