ChatGPT is an artificial intelligence chatbot developed by OpenAI and launched in November 2022. It is built on top of OpenAI's GPT-3.5 and GPT-4 families of large language models (LLMs) and has been fine-tuned (an approach to transfer learning) using both supervised and reinforcement learning techniques.

ChatGPT was launched on November 30, 2022, by San Francisco–based OpenAI. ChatGPT was launched as a prototype on November 30, 2022, and quickly garnered attention for its detailed responses and articulate answers across many domains of knowledge. Its uneven factual accuracy, however, has been identified as a significant drawback. Following the release of ChatGPT, OpenAI's valuation was estimated at US$29 billion in 2023.

ChatGPT was originally released in November 2022 based on GPT-3.5; GPT-4, the newest OpenAI model, was released on March 14, 2023, and is available for ChatGPT Plus users.