LlamaIndex
In one line
LlamaIndex is an LLM framework focused on RAG and data integration — a toolkit for indexing diverse documents, databases and APIs and connecting them to a model.
Going deeper
LlamaIndex started life as 'GPT Index' and stayed RAG-centric as it grew. It indexes heterogeneous sources — PDFs, Notion, Google Drive, Slack, SQL — and standardises the RAG pipeline pieces around them: chunking, embedding, routing, reranking.
The cleanest mental model is that LangChain and LangGraph emphasise the agent workflow side, while LlamaIndex emphasises the data side. Their feature surfaces overlap, but multi-source retrieval and evaluation tooling tend to be more polished in LlamaIndex.
Recent direction goes beyond plain RAG into managed infrastructure (LlamaCloud) and multi-agent patterns. For B2B teams that want an agent layer sitting cleanly on top of a real RAG stack, it has become an obvious starting point.
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