LlamaIndex

What It Does

LlamaIndex specializes in connecting LLMs with private and custom data sources. It provides sophisticated data ingestion, indexing, and retrieval pipelines that make it easy to build retrieval-augmented generation systems over any data.

Key Features

LlamaIndex offers data connectors for 160+ sources, customizable chunking and indexing strategies, multiple index types (vector, keyword, knowledge graph), query engines with response synthesis, and agent capabilities with tool use. LlamaCloud provides managed indexing.

When To Use It

Choose LlamaIndex when your primary need is connecting LLMs to custom data sources, building production RAG systems, or when data ingestion complexity is the main challenge. It excels at structured data querying and multi-document synthesis.

Alternatives

LangChain provides broader orchestration beyond retrieval. Haystack offers similar RAG capabilities with a different API design. For simple vector search, direct vector database integration may suffice.