# delay(for:tolerance:scheduler:options:) Delays delivery of all output to the downstream receiver by a specified amount of time on a particular scheduler. ``` func delay(for interval: S.SchedulerTimeType.Stride, tolerance: S.SchedulerTimeType.Stride? = nil, scheduler: S, options: S.SchedulerOptions? = nil) -> Publishers.Delay where S : Scheduler ``` ## Parameters `interval` The amount of time to delay. `tolerance` The allowed tolerance in delivering delayed events. The `Delay` publisher may deliver elements this much sooner or later than the interval specifies. `scheduler` The scheduler to deliver the delayed events. `options` Options relevant to the scheduler’s behavior. ## Return Value A publisher that delays delivery of elements and completion to the downstream receiver. ## Discussion Use [`delay(for:tolerance:scheduler:options:)`](/documentation/Combine/Publisher/delay(for:tolerance:scheduler:options:)) when you need to delay the delivery of elements to a downstream by a specified amount of time. In this example, a publishes an event every second. The [`delay(for:tolerance:scheduler:options:)`](/documentation/Combine/Publisher/delay(for:tolerance:scheduler:options:)) operator holds the delivery of the initial element for 3 seconds (±0.5 seconds), after which each element is delivered to the downstream on the main run loop after the specified delay: ``` let df = DateFormatter() df.dateStyle = .none df.timeStyle = .long cancellable = Timer.publish(every: 1.0, on: .main, in: .default) .autoconnect() .handleEvents(receiveOutput: { date in print ("Sending Timestamp \'\(df.string(from: date))\' to delay()") }) .delay(for: .seconds(3), scheduler: RunLoop.main, options: .none) .sink( receiveCompletion: { print ("completion: \($0)", terminator: "\n") }, receiveValue: { value in let now = Date() print ("At \(df.string(from: now)) received Timestamp \'\(df.string(from: value))\' sent: \(String(format: "%.2f", now.timeIntervalSince(value))) secs ago", terminator: "\n") } ) // Prints: // Sending Timestamp '5:02:33 PM PDT' to delay() // Sending Timestamp '5:02:34 PM PDT' to delay() // Sending Timestamp '5:02:35 PM PDT' to delay() // Sending Timestamp '5:02:36 PM PDT' to delay() // At 5:02:36 PM PDT received Timestamp '5:02:33 PM PDT' sent: 3.00 secs ago // Sending Timestamp '5:02:37 PM PDT' to delay() // At 5:02:37 PM PDT received Timestamp '5:02:34 PM PDT' sent: 3.00 secs ago // Sending Timestamp '5:02:38 PM PDT' to delay() // At 5:02:38 PM PDT received Timestamp '5:02:35 PM PDT' sent: 3.00 secs ago ``` The delay affects the delivery of elements and completion, but not of the original subscription. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)