The Nebius AI Builder Program is now available. AI isn’t just a model you call anymore. It’s a system you build. And builders, not a few closed labs, will decide what it becomes. The open ecosyst…

YouTube video by B.C. Begley

Andrej Karpathy said you could train an #opensource ChatGPT-like model from scratch for under $100. I wanted to see if that actually holds, so I tried the full NanoChat (https://lnkd.in/dTfWtFv2) on Nebius. ⚙️ I spun up an 8×H100 instance on Nebius, cloned karpathy/nanochat, and ran the full pipeline end-to-end. The steps: • Train a tokenizer on FineWeb-EDU (65K vocab) • Pretrain a 560M-parameter Transformer to predict the next token • Mid-train on conversational and reasoning data (SmolTalk, MMLU, GSM8K) • Supervised Finetuning — aligning it to chat format The results: ⏱️ The whole thing took a bit more than three hours. 💰 Cost: around $80 on Nebius . 📉 Validation bpb ≈ 0.81 📊 CORE ≈ 0.20 ⚡ MFU ≈ 48 % So yes, it really does train a ChatGPT-style model under $100. After the run, I opened the web UI and chatted with my model, and that’s the video below. It’s pretty wild that you can now train, fine-tune, and talk to your own LLM in an afternoon. Curious how the pipeli