# timeout(_:scheduler:options:customError:) Terminates publishing if the upstream publisher exceeds the specified time interval without producing an element. ``` func timeout(_ interval: S.SchedulerTimeType.Stride, scheduler: S, options: S.SchedulerOptions? = nil, customError: (() -> Self.Failure)? = nil) -> Publishers.Timeout where S : Scheduler ``` ## Parameters `interval` The maximum time interval the publisher can go without emitting an element, expressed in the time system of the scheduler. `scheduler` The scheduler on which to deliver events. `options` Scheduler options that customize the delivery of elements. `customError` A closure that executes if the publisher times out. The publisher sends the failure returned by this closure to the subscriber as the reason for termination. ## Return Value A publisher that terminates if the specified interval elapses with no events received from the upstream publisher. ## Discussion Use [`timeout(_:scheduler:options:customError:)`](/documentation/Combine/Publisher/timeout(_:scheduler:options:customError:)) to terminate a publisher if an element isn’t delivered within a timeout interval you specify. In the example below, a [`PassthroughSubject`](/documentation/Combine/PassthroughSubject) publishes elements and is configured to time out if no new elements are received within its `TIME_OUT` window of 5 seconds. A single value is published after the specified 2-second `WAIT_TIME`, after which no more elements are available; the publisher then times out and completes normally. ``` var WAIT_TIME : Int = 2 var TIMEOUT_TIME : Int = 5 let subject = PassthroughSubject() let cancellable = subject .timeout(.seconds(TIMEOUT_TIME), scheduler: DispatchQueue.main, options: nil, customError:nil) .sink( receiveCompletion: { print ("completion: \($0) at \(Date())") }, receiveValue: { print ("value: \($0) at \(Date())") } ) DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(WAIT_TIME), execute: { subject.send("Some data - sent after a delay of \(WAIT_TIME) seconds") } ) // Prints: value: Some data - sent after a delay of 2 seconds at 2020-03-10 23:47:59 +0000 // completion: finished at 2020-03-10 23:48:04 +0000 ``` If `customError` is `nil`, the publisher completes normally; if you provide a closure for the `customError` argument, the upstream publisher is instead terminated upon timeout, and the error is delivered to the downstream. --- 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)