OpenAI's branded premium speed tier. On September 29, 2026 OpenAI said Ultrafast offers up to 8x faster token generation (300 tokens per second) in Codex and up to 6x in the API, available that day for GPT-6 Astra in Codex, ChatGPT Work, and the API, with GPT-6.1 Sol coming soon. Codex and ChatGPT Work access is tied to the Pro 500 plan. An earlier August 2026 preview used the same name for GPT-5.6 Sol on Cerebras at up to 750 tokens per second with no public price — a different model and published speed. Treat API dollar rates as live-page facts; community quotes of a 6x Standard Ultrafast ladder were not independently verified in explainx.ai's DevDay write-up.