Overview
Most popular open-source framework for building LLM applications and agents in Python and JavaScript.
Details
LangChain is the most widely adopted open-source framework for building LLM applications and agents, available in Python and JavaScript/TypeScript. LangChain provides abstractions for prompts, models, retrieval, tools, agents, memory, and more, with hundreds of integrations across LLM providers, vector stores, and tools. The company behind LangChain also builds LangGraph (graph-based agent orchestration) and LangSmith (observability). LangChain has been foundational in establishing LLM application development patterns.