How ChatGPT-Style LLMs Are Built

HN's most frequent recommendation for a clear, approachable foundation in how LLMs work without heavy math.

Andrej Karpathy's three-hour-plus general-audience deep dive into how ChatGPT-style LLMs are built, covering the full training stack from pretraining to post-training. It also gives mental models for their quirks, like hallucination, and how to use them well.