ChatGPT is a conversational AI model developed by OpenAI, based on the GPT (Generative Pre-trained Transformer) architecture. It was launched in November 2022 and quickly became one of the fastest-growing applications in history, with over 100 million monthly active users within two months. ChatGPT is designed to generate human-like text responses, assist with various tasks, and support multiple languages. It has undergone several iterations, with improved reasoning, safety features, and multimodal capabilities.