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langchainvsllama_index

LangChain is broader — chains, agents, memory, integrations. LlamaIndex is RAG-first, optimized for indexing documents and retrieval. Use LlamaIndex inside LangChain for the best of both.

Option A
langchain-ai

langchain

github.com/langchain-ai/langchain

The biggest LLM framework. Chains, agents, RAG pipelines, integrations with every model, vector DB, and tool. Strong ecosystem with LangGraph for agentic workflows. The criticism: for simple use cases the abstractions feel heavy and the API has churned across versions. Worth it once your AI stack outgrows direct API calls.

Full review →
Option B
run-llama

llama_index

github.com/run-llama/llama_index

RAG specialist. Better document loading, chunking, and retrieval than LangChain for retrieval-first apps. Strong on advanced strategies — hybrid search, re-ranking, recursive retrieval. Now expanded into a general LLM toolkit but RAG is still the sweet spot.

Full review →

Which should you pick?

Pick langchain if…

You are building multi-step AI pipelines (agents, complex RAG, tool use) and need the ecosystem.

Skip langchain if…

You are just calling an LLM API and processing the response — use the native SDK directly.

Pick llama_index if…

Your AI app is mostly retrieval over documents — knowledge base, support bot, internal search.

Skip llama_index if…

You need broad agent/tool use — LangChain has wider integration coverage.

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More AI agents comparisons

langchain vs llama_index — GitHub Repo Comparison (Honest 2026 Take) — StackPicks — StackPicks