speed.md Codex Docs, 2026-03-14 00:32 UTC → 2026-03-20 00:35 UTC

8Fast mode is currently supported on GPT-5.4. When enabled, speed is increased8Fast mode is currently supported on GPT-5.4. When enabled, speed is increased

9by 1.5x and credits are consumed at a 2x rate.9by 1.5x and credits are consumed at a 2x rate.

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11Enable it by typing `/fast`. It’s available in Codex IDE Extensions, Codex11Use `/fast on`, `/fast off`, or `/fast status` in the CLI to change or inspect

12CLI, and the Codex app when you sign in with ChatGPT. With an API key, Codex12the current setting. You can also persist the default with `service_tier = "fast"` plus `[features].fast_mode = true` in `config.toml`. Fast mode is

13uses standard API pricing instead and you can’t use `/fast`.13available in the Codex IDE extension, Codex CLI, and the Codex app when you

14sign in with ChatGPT. With an API key, Codex uses standard API pricing instead

15and you can't use Fast mode credits.

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