LlamaIndex explained one concept at a time — documents and nodes, indexes and embeddings, retrievers, query engines, chat, agents, and workflows — for building data-centric LLM applications from prototype to production.
LlamaIndex began as the fastest way to build RAG and has grown into a full data framework for LLM applications — connect your data, index it, retrieve it, and reason over it, with agents and workflows on top.
LlamaIndex began as the fastest way to build RAG and has grown into a full data framework for LLM applications — connect your data, index it, retrieve it, and reason over it, with agents and workflows on top.
Everything LlamaIndex retrieves is a Node, and the quality of your Nodes — how you load your data and how you chunk it — sets the ceiling on everything downstream, no matter how good your model or retriever is.
Everything LlamaIndex retrieves is a Node, and the quality of your Nodes — how you load your data and how you chunk it — sets the ceiling on everything downstream, no matter how good your model or retriever is.
An index is the data structure that makes your Nodes findable, and for RAG that almost always means embeddings in a vector store — but LlamaIndex offers more than one index type, and knowing which organizes your data for which query pattern is the point.
An index is the data structure that makes your Nodes findable, and for RAG that almost always means embeddings in a vector store — but LlamaIndex offers more than one index type, and knowing which fits which query pattern is the point.
A retriever finds the relevant Nodes; a query engine turns those Nodes into a grounded answer. Together they are the RAG pipeline — and the seams between them (postprocessing, response synthesis) are where you tune quality.
A retriever finds the relevant Nodes; a query engine turns those Nodes into a grounded answer. Together they are the RAG pipeline — and the seams between them are where you tune quality.
A query engine answers one question in isolation; a chat engine holds a conversation. The difference is memory — and handling memory well is what separates a demo chatbot from one that stays coherent and affordable over a long dialogue.
A query engine answers one question in isolation; a chat engine holds a conversation. The difference is memory — and handling it well is what separates a demo chatbot from one that stays coherent and affordable over a long dialogue.
The moment you expose a query engine as a tool, RAG stops being a fixed pipeline and becomes a decision: the agent decides whether to retrieve, from which source, and whether one search was enough. That is agentic RAG, and it's built into LlamaIndex.
The moment you expose a query engine as a tool, RAG stops being a fixed pipeline and becomes a decision: the agent decides whether to retrieve, from which source, and whether one search was enough. That is agentic RAG.
An agent's reasoning loop is flexible but opaque and hard to control. A workflow is the opposite: you make the orchestration explicit as steps and events, trading some autonomy for the predictability, testability, and control that complex applications need.
An agent's reasoning loop is flexible but opaque and hard to control. A workflow is the opposite: you make orchestration explicit as steps and events, trading some autonomy for the predictability, testability, and control complex applications need.
A four-line RAG demo and a production RAG system share almost no operational concerns. Getting to production means treating ingestion as a pipeline, retrieval quality as something you measure, and the whole system as something you observe — the work that starts after the demo impresses everyone.
A four-line RAG demo and a production RAG system share almost no operational concerns. Getting to production means treating ingestion as a pipeline, retrieval quality as something you measure, and the whole system as something you observe.
This series is part of a larger body of work by Pratik Dhanave, an Agentic AI Architect writing about production AI systems, distributed systems, and cloud-native engineering. Explore all course series, browse every post, or find topics via the tag index.