ChatGPT is a language model developed by OpenAI. It is based on the GPT (Generative Pre-trained Transformer) architecture, specifically GPT-3.5. This model is designed to generate human-like responses to text-based inputs and engage in conversation with users. It has been trained on a diverse range of internet text to learn grammar, facts, reasoning abilities, and some level of common sense. ChatGPT can understand and generate coherent responses, providing information, answering questions, and engaging in dialogue on a wide variety of topics. It aims to simulate conversation with a human-like conversational partner.