LangChain is a software framework that helps facilitate the integration of large language models (LLMs) into applications.
[2] LangChain was launched in October 2022 as an open source project by Harrison Chase, while working at machine learning startup Robust Intelligence.
[4][5] In the third quarter of 2023, the LangChain Expression Language (LCEL) was introduced, which provides a declarative way to define chains of actions.
[6][7] In October 2023 LangChain introduced LangServe, a deployment tool to host LCEL code as a production-ready API.
[12] As of March 2023, LangChain included integrations with systems including Amazon, Google, and Microsoft Azure cloud storage;[13] API wrappers for news, movie information, and weather; Bash for summarization, syntax and semantics checking, and execution of shell scripts; multiple web scraping subsystems and templates; few-shot learning prompt generation support; finding and summarizing "todo" tasks in code; Google Drive documents, spreadsheets, and presentations summarization, extraction, and creation; Google Search and Microsoft Bing web search;[14] OpenAI, Anthropic, and Hugging Face language models; iFixit repair guides and wikis search and summarization; MapReduce for question answering, combining documents, and question generation; N-gram overlap scoring; PyPDF, pdfminer, fitz, and pymupdf for PDF file text extraction and manipulation; Python and JavaScript code generation, analysis, and debugging; Milvus vector database[15] to store and retrieve vector embeddings; Weaviate vector database[16] to cache embedding and data objects; Redis cache database storage; Python RequestsWrapper and other methods for API requests; SQL and NoSQL databases including JSON support; Streamlit, including for logging; text mapping for k-nearest neighbors search; time zone conversion and calendar operations; tracing and recording stack symbols in threaded and asynchronous subprocess runs; and the Wolfram Alpha website and SDK.