GPT-5.3 Instant
OpenAI · 2026-03-03
GPT-5.3 Instant is OpenAI's conversational ChatGPT model, publicly released on March 3, 2026 and replaced by GPT-5.5 Instant as the default model in May 2026. OpenAI exposed it through the model-specific gpt-5.3-chat-latest API alias, which it updated on March 16, and lists no separate dated snapshot. It improved web-grounded accuracy, reduced unnecessary refusals and moralizing preambles, and strengthened writing range and conversational directness relative to GPT-5.2 Instant.