GPT-5.4 is OpenAI's most capable model yet, combining coding, computer operation, and reasoning in a single package for the first time.
OpenAI has released GPT-5.4, available in ChatGPT as GPT-5.4 Thinking, in the API, and in Codex. Alongside it comes GPT-5.4 Pro, a beefed-up version built for particularly complex tasks. OpenAI calls it the company's "most capable and efficient frontier model for professional work."
For the first time, the model combines the coding capabilities of the recently released GPT-5.3 Codex with improved reasoning, agentic workflows, and native computer use. OpenAI describes GPT-5.4 as the first "mainline reasoning model" to integrate the frontier coding capabilities of GPT-5.3 Codex. There was no 5.3 Thinking model, only the Codex variant. The numbering reflects this leap and is meant to simplify model selection in Codex, OpenAI says.
The company just shipped the 5.3 Instant model on Tuesday, which currently serves as the default chat model in ChatGPT. Going forward, OpenAI says Instant and Thinking models will continue to develop at different speeds.
GPT-5.4 matches or beats professionals across 44 occupations in academic benchmark
