What is MERN AI chatbot development?

MERN AI chatbot development means building a production conversational AI on the MERN stack: LangChain.js for orchestration on the Express backend, MongoDB for conversation memory and vector retrieval, and React for a streaming chat UI. The four common chatbot patterns are customer support (RAG over help docs), internal knowledge (employee Q and A), agentic workflows (multi-step task automation), and product-embedded assistants (in-app onboarding and sales). Every serious MERN chatbot ships with an evaluation suite, guardrails, cost caps, and observability.