GPT-5.4-mini can be accessed today by choosing «Thinking» from the model picker on the Free and Pro tiers.
The model is stronger than 5-mini on reasoning, multimodal understanding, tool use and subagents, OpenAI says.
It is also available in Codex, where it uses only 30% of tokens for the same task compared to 5.4 proper — and is usable for workloads where latency and speed are important.
Also introduced today is GPT-5.4-nano, which is for the times when speed and cost matter most. It costs only $0.20/$1.25 per 1M tokens, and is handy for mass classification, ranking, coding subagents and compaction.
Nano doesn’t support web search or computer use, and is only available in the API.
Read more: OpenAI’s introduction, Tibor Blaho on X.com, Engadget.