minGPT
A minimal PyTorch re-implementation of the OpenAI GPT
...It strips away extraneous bells and whistles, aiming to show how a sequence of token indices is fed into a stack of transformer blocks and then decoded into the next token probabilities, with both training and inference supported. Because the whole model is around 300 lines of code, users can follow each step—from embedding lookup, positional encodings, multi-head attention, feed-forward layers, to output heads—and thus demystify how GPT-style models work beneath the surface. It provides a practical sandbox for experimentation, letting learners tweak the architecture, dataset, or training loop without being overwhelmed by framework abstraction.