LangChain and LlamaIndex diverge in AI development focus

LangChain and LlamaIndex, once viewed as direct rivals in the retrieval-augmented generation (RAG) space, have evolved into distinct specialized platforms.

LangChain has transitioned into an agent engineering platform. Its ecosystem now focuses on building AI agents through frameworks such as LangGraph and Deep Agents, supported by LangSmith for observability, evaluation, and deployment. Its core functionality centers on the ‘create_agent’ harness, which integrates models, tools, and prompts.

In contrast, LlamaIndex has positioned itself as a document processing platform. It focuses on the frontier of document parsing and extraction, utilizing tools like LlamaParse for agentic OCR and structured extraction, as well as LiteParse for fast local parsing.

Both projects remain open source under the MIT license, allowing developers to combine them by using LlamaIndex for data cleaning and extraction and LangChain for agent construction.