LangChain vs LlamaIndex: Which Python AI Framework to Choose (2026)

Choosing between LangChain and LlamaIndex is one of the first decisions you face when building a Python AI application in 2026. Both frameworks accelerate LLM development, both are open source, and both have active communities — but they solve different problems. Originally published at kalyna.pro What Is LangChain? LangChain is a framework for building applications powered by language models. Its core idea is composability: you chain together prompts, models, tools, memory, and a...