LangChain began as a side project of Harrison Chase in late 2022, just as ChatGPT was about to put large language models in front of a mass audience. Chase and co-founder Ankush Gola turned it into a company in 2023. The project’s premise was that a useful application is rarely a single model call: it is a model wired to data sources, external tools, memory, and control logic.
LangChain provides standard interfaces and integrations for the moving parts of an LLM application, models, embeddings, vector stores, and tools, and lets developers compose them into chains and agents. Its large library of third-party integrations meant developers could swap providers or add a vector database without rewriting their app. The project later grew an ecosystem around it, including LangGraph for agent orchestration and LangSmith for debugging and monitoring. The company reports more than a billion open-source downloads and use by a large share of the Fortune 500.
LangChain matters as the framework that gave the post-ChatGPT wave of LLM apps a common vocabulary, of chains, agents, retrievers, and tools, even as critics argued its abstractions could be heavier than building directly against model APIs.