LlamaIndex

LlamaIndex is a data framework that helps developers connect large language models to external data sources for retrieval-augmented generation (RAG), knowledge management, and data-grounded AI applications. It provides data connectors, index structures, and query engines that simplify building production RAG systems. AI engineers building document Q&A systems, enterprise search applications, and data-grounded chatbots use LlamaIndex to handle the data ingestion, chunking, embedding, and retrieval pipeline. It supports 150+ data connectors for common data sources. LlamaIndex and LangChain are the two dominant open-source AI application frameworks, with LlamaIndex focusing specifically on the data layer (retrieval, indexing, and querying) while LangChain provides broader orchestration capabilities. Many production systems use both.