Fullstack Engineer

Ethereum Technologies LLC; Sunnyvale (CA); On-site; USD 140,000 - 200,000; Full time

Job summary

Ethereum Technologies LLC is seeking a versatile Full-Stack Engineer to build production-grade web apps and design AI-powered agents using LangChain and LangGraph. You will implement responsive interfaces with React and robust backends with Python, while ensuring secure, scalable APIs and efficient workflows.

The role emphasizes integrating LLMs, tool-calling, memory, and multi-step reasoning, plus crafting RAG-based solutions with embeddings and vector databases.

Qualifications

• Proficiency in building production-grade web apps with React frontend and Python backend.
• Strong understanding of full-stack architecture, REST APIs and scalability.
• Hands-on experience with LangChain for LLM app development and LangGraph for orchestration.
• Knowledge of RAG, embeddings, vector databases and secure code practices.

Responsibilities

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

Skills

React

Python

LangChain

LangGraph

REST APIs

RAG architectures

Embeddings

Vector databases

Tools

Git

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

ETHEREUM 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. ETHEREUM 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 ETHEREUM 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