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mediumLangChainOpenAI

LangChain, LlamaIndex, LangGraph, what are the real differences, and when would you use each?

Asked constantly in GenAI loops, and most answers are marketing-page recitals. The version that scores: classify by what each actually is, data framework, integration toolkit, graph runtime, then give the selection criteria that outlive all three names.

Updated Aug 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.

Asked constantly in GenAI loops, and most answers are marketing-page recitals. The version that scores: classify by what each actually is, data framework, integration toolkit, graph runtime, then give the selection criteria that outlive all three names.

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