LangChain

Provider: LangChain

LangChain offers a rich modular API ecosystem—supporting chains (prompt→LLM→tool), agent orchestration via LangGraph, and observability through LangSmith. It integrates with major LLM providers and vector/data stores, and supports hosting options from local to cloud. Its widely used to build retrieval-augmented generation workflows, multi-step reasoning agents, code assistants, chatbots, and document analysis tools

Free