# Cooldown `function` in `core` · v0.12.0 Allows `limit` uses per window, scoped by `per`. A number `duration` is **seconds**, and a string is a duration like `30m` or `24h`. The slot is charged in commit, only after the whole gate set passes, so a later refusal never burns the cooldown. If two requests in one process pass the check together, the commit refuses the one that goes over `limit`. The key combines the handler's route with the window settings, keeping two different handlers on separate windows. Replace the refusal with [`notice`](/docs/packages/core/0.12.0/interfaces/cooldown-options#notice). ```ts Cooldown( duration: number | ValidDuration, options?: CooldownOptions ): EffectGate ``` Allows `limit` uses per window, scoped by `per`. A number `duration` is **seconds**, and a string is a duration like `30m` or `24h`. The slot is charged in commit, only after the whole gate set passes, so a later refusal never burns the cooldown. If two requests in one process pass the check together, the commit refuses the one that goes over `limit`. The key combines the handler's route with the window settings, keeping two different handlers on separate windows. Replace the refusal with [`notice`](/docs/packages/core/0.12.0/interfaces/cooldown-options#notice). Parameters. - `duration` `number | ValidDuration` — A number is seconds, and a string is a duration like `30m` or `24h`. - `options?` `CooldownOptions` — Sets the scope with `per`, the uses per window with `limit`, and the refusal with `notice`. Returns `EffectGate`.