General: DevForums tag: Background Tasks Background Tasks framework documentation UIApplication background tasks documentation ProcessInfo expiring activity documentation watchOS background execution documentation WWDC 2020 Session 10063 Background execution demystified — This is critical resource. Watch it! WWDC 2022 Session 10142 Efficiency awaits: Background tasks in SwiftUI iOS Background Execution Limits DevForums post UIApplication Background Task Notes DevForums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"

Hello, aspiring programmer here. I am developing a StepCounter APP, which keeps track of how many steps I have taken and sends to an MQTT server. I am trying to make this happen even while the app is not in focus, but so far I have not been able to get this working. First tried with silent background music, which seemed pretty inconsistent and inpractical, since I usually play youtube videoes while walking, making the app stop with its silent audio. Then tried GPS, which didnt really do anything (could be implementation problem). Has anyone made background processing work for their apps?

Hello, aspiring programmer here. I am developing a StepCounter APP, which keeps track of how many steps I have taken and sends to an MQTT server. I am trying to make this happen even while the app is not in focus, but so far I have not been able to get this working. First tried with silent background music, which seemed pretty inconsistent and inpractical, since I usually play youtube videoes while walking, making the app stop with its silent audio. Then tried GPS, which didnt really do anything (could be implementation problem). Has anyone made background processing work for their apps?

Hi everyone, We're experiencing an issue with our Flutter app that uses PushKit, CallKit, and Janus for handling VoIP calls. Everything works fine when the app is in the foreground, but when the app is in the background or completely closed (terminated state), the behavior is inconsistent: Sometimes, incoming calls are received as expected. Other times, the app does nothing, and the call is not delivered at all. Upon checking the console logs, we noticed that our app is being canceled (terminated by the system), which seems to be the reason why calls are not coming through. This happens randomly, making it difficult to reproduce consistently. Additional Details: The app is configured to handle VoIP notifications correctly. We are using PushKit to wake up the app and trigger CallKit for the incoming call UI. When the app is active, calls are handled correctly via Janus WebRTC signaling. We have verified that background modes for VoIP are enabled in the Info.plist. We suspect that iOS may be aggressively killing the app in the background, preventing incoming call notifications from reaching it. Questions: Has anyone experienced similar behavior with PushKit + CallKit on recent iOS versions? Could iOS be terminating the app due to background execution policies? Are there recommended best practices to ensure reliable delivery of VoIP notifications when the app is closed? Any insights or suggestions would be greatly appreciated! Thanks! Addional Information: this is the cancellation information at console: Received incoming message on topic hiperme.app at priority 10 por omisión 17:10:18.462084-0300 dasd CANCELED: com.apple.pushLaunch.hiperme.app:E8BACD at priority 10

If new photo is added to library and app is not running in foreground or was not opened after the new photo was added but the app is having full access to gallery, can it access, read the new photo - If the app is not specifically a cloud syncing app, can it have this attached function, suppose it is a game app or beauty camera app?

My team is designing an app for retail associates that need to share managed iPads. We keep the app in Guided Access mode on our login app until an auth token is obtained. Then the iPad is opened for general use. Upon signout we need to re-enter guided access mode and we can do this via manual signout easily. But with idle signout, ie after 60 minutes of inactivity, we need to be able to make a call from the background (in a locked state even) and sign out the user, clear the pin code and enter single app mode before restarting. So that hopefully once the device restarts, we have the app in a locked state again until the next user provides credentials that can obtain a new auth token. We are struggling to see if this is even possible. Our bosses will be displeased if we tell them it isn't. So anybody with any tips would be very appreciated.

I have BGProcessingTask & BGAppRefreshTask working fine. The main purpose of my use of BGProcessingTask is to upload a file to AWS S3 using multipart/form-data. I have found that any file above about 2.5MB times out after running almost four minutes. If I run the same RESTful api using curl or Postman, I can upload a 25MB file in 3 seconds or less. I have tried to deliberately set .earliestBeginDate to 01:00 or 02:00 local time on the iPhone, but that does not seem to help. I use the delegate (yes, I am writing in Objective C) - URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend: and find that the iOS system uploads about 140kB every 15 seconds or so. I am looking for recommendations or insight into how I might enable uploads of 25MB files. I would be happy it I could do just one a day for my use case. I provide code on how I set up the NSURLSession and NSURLSessionDownloadTask, as it is my guess that if there is something that needs to be modified it is there. I have to believe there is a solution for this since I read in many posts here and in StackOverflow how developers are using this functionality for uploading many, many files. NSURLSessionConfiguration *sConf = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:bkto.taskIdentifier]; sConf.URLCache = [NSURLCache sharedURLCache]; sConf.waitsForConnectivity = YES; sConf.allowsCellularAccess = NO; sConf.networkServiceType = NSURLNetworkServiceTypeVideot; sConf.multipathServiceType = NSURLSessionMultipathServiceTypeNone; sConf.discretionary = YES; sConf.timeoutIntervalForResource = kONEHOURINTERVAL; sConf.timeoutIntervalForRequest = kONEMINUTEINTERVAL; sConf.allowsExpensiveNetworkAccess = NO ; sConf.allowsConstrainedNetworkAccess = NO; sConf.sessionSendsLaunchEvents = YES; myURLSession = [NSURLSession sessionWithConfiguration:sConf delegate:self delegateQueue:nil]; And then later in the code... NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:pth]]; request.HTTPMethod = kHTTPPOST; request.HTTPBody = [NSData my body data]; request.timeoutInterval = 60; [request setValue:@"*/*" forHTTPHeaderField:@"Accept"]; [request setValue:@"en-us,en" forHTTPHeaderField:@"Accept-Language"]; [request setValue:@"gzip, deflate, br" forHTTPHeaderField:@"Accept-Encoding"]; [request setValue:@"ISO-8859-1,utf-8" forHTTPHeaderField:@"Accept-Charset"]; [request setValue:@"600" forHTTPHeaderField:@"Keep-Alive"]; [request setValue:@"keep-alive" forHTTPHeaderField:@"Connection"]; NSString *contType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",bnd]; [request setValue:contType forHTTPHeaderField:@"Content-Type"]; [request addValue:[NSString stringWithFormat:@"%lu",(unsigned long)myData.length] forHTTPHeaderField:@"Content-Length"]; and here are a few lines from my logs to show the infrequent multi-part uploads of only small chunks of data by the iOS system: -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 393,216 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 393,216 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:27 2025 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 524,288 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:42 2025 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 655,360 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:56 2025 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072 -[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 786,432

I have an app that uses background audio recording. From what others say, I have enabled the audio background mode to keep the audio session active, and this worked. But when submitting the app to the app store, the app was rejected because the audio background mode is only supposed to be used for audio playback. How do I create this background mode while following Apple's guidelines?

I've been reading this question: https://developer.apple.com/forums/thread/701945 and watching the videos on background tasks But can't arrive to a concrete solution. Q1: Are there any tips (or sample app) on how to handle a launch in background in a streamlined way? How to have a shared code that is ran for both 'launch in background' & 'launch in foreground'? Specifically the case I'm talking about is: You set up some observance of some OS callback at a Foo screen of your app. Example app should request and then send push-to-start live activity tokens to server. Or setup location tracking. App is then suspended and then later terminated but is eligible for relaunch App is then launched in background because it has requested a push-to-start live activity token or an update for location tracking. User DOES NOT go back to screen Foo. So at this point app is no longer tracking / listening to updates for token update or location changes. How should I architecture my code for this? I'm trying to see if there's a an approach where I can avoid having multiple places in code where I do the same thing. Currently what I'm doing is as such: Q2: Is it then correct to say that anytime you've launched your app, whether it's in foreground or background then you must immediately match 'all observations done by the previous app launch'? Like store items in UserDefaults and upon launch retrieve them and do: handleGeneralAppLaunchFlow() // ALSO if defaults.contains("didLastLaunchSetupLiveActivtiyTokenObservance") { for await ptsToken in Activity<EmojiRangers> .pushToStartTokenUpdates { ... } } if defaults.contains("didLastLaunchSetupLocationTracking") { locationManager = CLLocationManager() locationManager?.delegate = itsDelegate locationManager?.allowsBackgroundLocationUpdates = true locationManager?.showsBackgroundLocationIndicator = true locationManager?.startUpdatingLocation() } // Other checks for prior observance setup Q3: Actually I think even if app is launched in foreground then because you may not end up at screen Foo again, then you must setup things regardless of app state and just based on prior observations set. Right? Q4: And then later if the user ever made it again to screen Foo, then we just skip the re-do of the observance, or maybe to just keep things simple, we'd just redo without over-engineering things? I tried to mark my questions with Q1- Q4.

We've seen a recent increase in background terminations: blue - System Pressure orange - Task Timeout I'm trying to understand the increase in system-pressure terminations, since there's no corresponding increase in memory at suspension. Are there other system resources for which iOS will terminate an app?

Hi all, I've been trying to test the suspension -> resume behaviour of our app, on iPad (iPadOS 18.3.1), however I'm unable to reliably get the application into a suspended state. Things I've read that do not work reliably: Backgrounding the application and waiting ~1 minute Backgrounding the application and opening a bunch of other applications Sometimes it will work consistently, then other times I can be waiting for 30 minutes or more and it still won't suspend. If it matters - I'm launching the app via xcode & it's also a capacitor app with a web sockets connection. Is there any way to reliably suspend an app? Thanks

When using the old withTaskCancellationHandler(operation:onCancel:isolation:) to run background tasks, you were notified that the background task gets cancelled via the handler being called. SwiftUI provides the backgroundTask(_:action:) modifier which looks quite handy. However how can I check if the background task will be cancelled to avoid being terminated by the system? I have tried to check that via Task.isCancelled but this always returns false no matter what. Is this not possible when using the modifier in which case I should file a bug report? Thanks for your help

Desired Behavior I want the app to be able to handle multiple Push-to-Start notifications even when it is completely terminated. Each Live Activity should: Be successfully displayed upon receiving a Push-to-Start notification. Trigger background tasks to send its update token to the server, regardless of the time interval between notifications. Problem I am facing an issue with iOS Live Activities when using Push-to-Start notifications to trigger Live Activities in an app that has been completely terminated. Here’s the detailed scenario: When the app is completely terminated and I send the first Push-to-Start notification: The Live Activity is successfully displayed. didFinishLaunchingWithOptions` is triggered, and background tasks execute correctly, including sending the update token to the server. When I send consecutive Push-to-Start notifications in quick succession (e.g., within a few seconds or minutes): Both notifications successfully display their respective Live Activities. Background tasks are executed correctly for both notifications. However, when there is a longer interval (e.g., 10 minutes) between two Push-to-Start notifications: The first notification works perfectly—it displays the Live Activity, triggers didFinishLaunchingWithOptions, and executes background tasks. The second notification successfully displays the Live Activity but fails to execute any background tasks, such as sending the update token to the server. My HypothesisI suspect that iOS might impose a restriction where background runtime for Push-to-Start notifications can only be granted once within a certain time frame after the app has been terminated. Any insights into why this issue might be occurring or how to ensure consistent background task execution for multiple Push-to-Start notifications would be greatly appreciated!

Hello Apple Developer Community, I am developing a medical app that is classified as Class B according to FDA regulations. The app connects to a medical device using Bluetooth Low Energy (BLE) to collect critical medical data such as ECG readings. To ensure accurate data collection and maintain the quality of the medical readings, the app needs to wake up every five minutes in the background and perform tasks for approximately 30 seconds. I understand that iOS has strict limitations on background execution to preserve battery and system performance. However, due to the medical nature of the app and the need for periodic data collection, I am seeking guidance on the following: If I can provide documentation that the app is associated with an FDA-approved Class B medical device, would Apple allow more lenient background task execution policies? Are there specific APIs, such as BackgroundTasks, CoreBluetooth, or other recommended strategies, that could help me achieve this behavior reliably? Is there a process to apply for an exception or special consideration for medical apps that require periodic background activity? Any insights or recommendations would be greatly appreciated. Thank you!

Hello, I’m experiencing an issue with my iOS app that uses CoreBluetooth in combination with beacon monitoring. My app is designed to wake via beacon region monitoring and then start scanning for a specific BLE peripheral (with specific service UUIDs). When the device screen is bright (i.e., the device is unlocked, or locked but the screen is active/bright), everything works perfectly—the connection is established and maintained without any issues in both: foreground and background. However, when the device is left alone for a while and the lock-screen dims (sleeps), the app continues to run in the background and range the beacon (I can confirm this via realtime console logs), but the connection attempt fails. Here’s what I observe: The central manager’s delegate method didConnect is called, indicating that the peripheral was connected. Almost immediately afterward, didDisconnect is triggered with the error message: "The specified device has disconnected from us.". The interesting part is (I repeatedly see this error in the console, because the app repeatedly tries to connect to peripheral until a success), when I touch the lockscreen (not unlock, but just touch, which makes the screen to light up brighter), the connection is being established without any further issues! I have the necessary background modes enabled in the app’s capabilities (e.g., bluetooth-central, location-always-mode, etc..). My expectation was that, thanks to beacon monitoring, the app would be awakened when needed, and scanning/connection would work reliably in the background regardless of whether the device is active or dimmed. My questions are: Why might the connection fail with this error when the device is locked/dimmed? Is this behavior expected due to iOS power management policies even if the app remains active in the background? Is there a way to ensure a reliable connection in such cases? Any insights, workarounds, or suggestions would be greatly appreciated. Thank you in advance!

I've been having trouble with .backgroundTask(.appRefresh()) causing an intermittent crash when my app is launched. When the crash happens, the app flashes a darkened screen with the home screen device information (time-of-day, battery life, etc) weirdly pivoted landscape and right-justified. This screen shows for a split-second, disappears, and the app does NOT launch. Re-tapping the app icon will often re-launch the app without incident. After much trouble-shooting, I've discovered that commenting out EITHER @Environment(\.scenePhase) private var phase or the .backgroundTask(.appRefresh()) {} code eliminates the crash, so it's somehow caused by having both present at the same time. As you can see in the example below, it's not even necessary to actually use .scenePhase or .backgroundTask to run any other code in order to create the crash. The following minimal reproducible example will create the crash on an actual device, although you may need to launch and quit the app in quick succession 10-20 times to see the crash. (I realize most users aren't likely to do that - sometimes the crash occurs in the actual app on the first launch. But it's an intermittent problem so may require a few testing rounds to appear.) In addition to the code shown here, I've added the "Background Modes" capability with "Background Fetch" to "Signing & Capabilities" and added the "UpdateBadge" task to "Info" as a "Permitted background task scheduler identifier". Any idea what could be causing the crash and how to prevent it? struct ToyBackgroundTasksApp: App { @Environment(\.scenePhase) private var phase var sharedModelContainer: ModelContainer = { let schema = Schema([ Item.self, ]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { return try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() var body: some Scene { WindowGroup { ContentView() } .modelContainer(sharedModelContainer) .backgroundTask(.appRefresh("UpdateBadge")) { print("background task") } } }

I have currently created an app which contains an upload button which when clicked upload health data using HealthKit to an AWS S3 bucket. Now I want to implement an automatic file upload mechanism which would mean that the app is installed and opened just once - and then the upload must happen on a schedule (once daily) from the background without ever having to open the app again. I've tried frameworks like NSURLSession and BackgroundTasks but nothing seems to work. Is this use case even possible to implement? Does iOS allow this? The file is just a few KBs in size. For reference, here is the Background Tasks code: import UIKit import BackgroundTasks import HealthKit class AppDelegate: NSObject, UIApplicationDelegate { let backgroundTaskIdentifier = "com.yourapp.healthdata.upload" func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -&gt; Bool { // Register the background task BGTaskScheduler.shared.register(forTaskWithIdentifier: backgroundTaskIdentifier, using: nil) { task in self.handleHealthDataUpload(task: task as! BGAppRefreshTask) } // Schedule the first upload task scheduleDailyUpload() return true } // Schedule the background task for daily execution func scheduleDailyUpload() { print("[AppDelegate] Scheduling daily background task.") let request = BGAppRefreshTaskRequest(identifier: backgroundTaskIdentifier) request.earliestBeginDate = Date(timeIntervalSinceNow: 24*60*60) do { try BGTaskScheduler.shared.submit(request) print("[AppDelegate] Daily background task scheduled.") } catch { print("[AppDelegate] Could not schedule daily background task: \(error.localizedDescription)") } } // Handle the background task when it's triggered by the system func handleHealthDataUpload(task: BGAppRefreshTask) { print("[AppDelegate] Background task triggered.") // Call your upload function with completion handler HealthStoreManager.shared.fetchAndUploadHealthData { success in if success { print("[AppDelegate] Upload completed successfully.") task.setTaskCompleted(success: true) // Schedule the next day's upload after a successful upload self.scheduleDailyUpload() } else { print("[AppDelegate] Upload failed.") task.setTaskCompleted(success: false) } } // Handle task expiration (e.g., if upload takes too long) task.expirationHandler = { print("[AppDelegate] Background task expired.") task.setTaskCompleted(success: false) } } }

I've been seeing a high number of BGTaskScheduler related crashes, all of them coming from iOS 18.4. I've encountered this myself once on launch upon installing my app, but haven't been able to reproduce it since, even after doing multiple relaunches and reinstalls. Crash report attached at the bottom of this post. I am not even able to symbolicate the reports despite having the archive on my MacBook: Does anyone know if this is an iOS 18.4 bug or am I doing something wrong when scheduling the task? Below is my code for scheduling the background task on the view that appears when my app launches: .onChange(of: scenePhase) { newPhase in if newPhase == .active { #if !os(macOS) let request = BGAppRefreshTaskRequest(identifier: "notifications") request.earliestBeginDate = Calendar.current.date(byAdding: .hour, value: 3, to: Date()) do { try BGTaskScheduler.shared.submit(request) Logger.notifications.log("Background task scheduled. Earliest begin date: \(request.earliestBeginDate?.description ?? "nil", privacy: .public)") } catch let error { // print("Scheduling Error \(error.localizedDescription)") Logger.notifications.error("Error scheduling background task: \(error.localizedDescription, privacy: .public)") } #endif ... } 2025-02-23_19-53-50.2294_+0000-876d2b8ec083447af883961da90398f00562f781.crash

I am developing an App that will enable voice calls between users through webrtc. When the user opens the App and switches the App to the background, the user will receive the incoming call notification through Silent Push Notifications (not PushKit). My question is as follows, If set UIBackgroundModes to voip and do not use PushKit and CallKit, will this cause the background App to be unable to use webrtc voice calls (requires network, microphone, and audio permissions)? Can I set UIBackgroundModes = audio combined with AVAudioSession playAndRecord instead of setting UIBackgroundModes to voip, so that I can use the microphone and audio in the background to implement webrtc voice calls? Thanks for your help.

When I run my app with XCode on my iPhone, and then moved into the background, I'm getting a EXC_BREAKPOINT exception after a few minutes, seemingly when iOS attempts to call my app with a BGAppRefreshTask: Thread 23 Queue: com.apple.BGTaskScheduler (com.mycompany.MyApp.RefreshTask) (serial) 0 _dispatch_assert_queue_fail 12 _pthread_wqthread Enqueued from com.apple.duet.activityscheduler.client.xpcqueue (Thread 23) 0 dispatch_async 20 start_wqthread I can't quite understand the reason from this crash. In the background task, I'm attempting to update live activities. In the process, it might encounter code that calls MainActor and manipulate @Observable objects. Might that be the reason?