GPT-5.3 Instant is OpenAI's latest conversational AI model, featuring reduced unnecessary refusals, improved factual accuracy, and more natural conversational tone. The model reduces hallucinations by up to 26.8% in high-stakes domains like medicine, law, and finance when using web search, and by 19.7% without web access. It provides direct answers to safe questions while minimizing defensive preambles, improved web result synthesis that prioritizes relevant context over link lists, and stronger writing capabilities for both practical and creative tasks. The model is available to all ChatGPT users and developers through the API as gpt-5.3-chat-latest.