nanochat (via) Really interesting new project from Andrej Karpathy, described at length in this discussion post.
It provides a full ChatGPT-style LLM, including training, inference and a web Ui, that can be trained for as little as $100:
This repo is a full-stack implementation of an LLM like ChatGPT in a single, clean, minimal, hackable, dependency-lite codebase.
It's around 8,000 lines of code, mostly Python (using PyTorch) plus a little bit of Rust for training the tokenizer.
Andrej suggests renting a 8XH100 NVIDA node for around $24/ hour to train the model. 4 hours (~$100) is enough to get a model that can hold a conversation - almost coherent example here. Run it for 12 hours and you get something that slightly outperforms GPT-2. I'm looking forward to hearing results from longer training runs!
The resulting model is ~561M parameters, so it should run on almost anything. I've run a 4B model on my iPhone, 561M should easily fit on even an inexpensive Raspberry Pi.
The model defaults to training on ~24GB from karpathy/fineweb-edu-100b-shuffle derived from FineWeb-Edu, and then midtrains on 568K examples from SmolTalk (460K), MMLU auxiliary train (100K), and GSM8K (8K), followed by supervised finetuning on 21.4K examples from ARC-Easy (2.3K), ARC-Challenge (1.1K), GSM8K (8K), and SmolTalk (10K).
Here's the code for the web server, which is fronted by this pleasantly succinct vanilla JavaScript HTML+JavaScript frontend.
Update: Sam Dobson pushed a build of the model to sdobson/nanochat on Hugging Face. It's designed to run on CUDA but I pointed Claude Code at a checkout and had it hack around until it figured out how to run it on CPU on macOS, which eventually resulted in this script which I've published as a Gist. You should be able to try out the model using uv like this:
cd /tmp
git clone https://huggingface.co/sdobson/nanochat
uv run https://gist.githubusercontent.com/simonw/912623bf00d6c13cc0211508969a100a/raw/80f79c6a6f1e1b5d4485368ef3ddafa5ce853131/generate_cpu.py \
--model-dir /tmp/nanochat \
--prompt "Tell me about dogs."
I got this (truncated because it ran out of tokens):
I'm delighted to share my passion for dogs with you. As a veterinary doctor, I've had the privilege of helping many pet owners care for their furry friends. There's something special about training, about being a part of their lives, and about seeing their faces light up when they see their favorite treats or toys.
I've had the chance to work with over 1,000 dogs, and I must say, it's a rewarding experience. The bond between owner and pet