Let's Build GPT: From Scratch, in Code

Karpathy builds a GPT model from scratch in Python/PyTorch, live on camera — from the basic bigram model all the way to a working transformer with self-attention. The clearest hands-on explanation of how GPT architectures actually work.

Following the nanoGPT codebase, Karpathy takes viewers from a simple character-level language model to a full GPT transformer, explaining every line of code and every architectural decision along the way. Topics include token embeddings, multi-head self-attention, positional encodings, layer normalization, and the decoder-only transformer block. One of the highest-rated coding tutorials in AI education.

GPTTransformersPyTorchNanoGPTSelf-AttentionCoding TutorialAndrej Karpathy

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