OpenAI introduced GPT-5.4 across ChatGPT, Codex, and API

OpenAI launched GPT-5.4 on March 5, 2026, with rollout to paid ChatGPT users, all Codex users, and immediate API availability. OpenAI also exposed GPT-5.4 Pro in the API, pricing GPT-5.4 at $2.50 input / $0.25 cached input / $15 output per 1M tokens and GPT-5.4 Pro at $30 input / $180 output per 1M tokens.