// Hacker Noon · 24 January 2026

RAG Systems in Five Levels of Difficulty (With Full Code Examples)

Most RAG systems fail in production because “semantic similarity” isn’t the same as relevance, and retrieval breaks under real queries. This article outlines five escalating levels—naive RAG, smarter chunking with overlap and metadata, hybrid semantic + BM25 retrieval, cross-encoder reranking, and p...

Hacker Noon

@hacker-noon · Paolo Perrone

hackernoon.com

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