OpenAI has released ChatGPT 5.1, featuring two modes: Instant for casual conversations and Thinking for deeper reasoning. The update also allows users to customize tone and style more precisely, improving user experience for both personal and brand interactions.

nanochat is a full-stack implementation of a ChatGPT-like language model that can be trained on an 8XH100 GPU node for about $800. It features a simple UI for interaction and is designed to be highly configurable and hackable by users, allowing them to train and customize their own models. While it currently outperforms GPT-2, it still has limitations compared to more advanced models like GPT-5.