LangChain - Build LLM Applications with Agents & RAG The most popular framework for building LLM-powered applications. When to use LangChain Use LangChain when: - Building agents with tool calling and reasoning (ReAct pattern) - Implementing RAG (retrieval-augmented generation) pipelines - Need to swap LLM providers easily (OpenAI, Anthropic, Google) - Creating chatbots with conversation memory - Rapid prototyping of LLM applications - Production deployments with LangSmith observability Metrics : - 119,000+ GitHub stars - 272,000+ repositories use LangChain - 500+ integrations (models, vector…