Is there any way to find what apps are downloading stuff in the background? And what stuff they are downloading? I've done a little research and gather it's the Background Transfer Service doing the work. But no hint of how to monitor what its doing. This other question is a bit more general and the answer was "there's no way to know" but it's a bit old and the answers aren't authoritative.

About once a week when I plug my phone in and it's on WiFi I find it's suddenly downloading hundreds of megabytes of data. I can figure out a bit of what's going on from my router, an HTTP connection to aaplimg.com, but all that tells me is it's something on Apple's CDN. Short of running a packet sniffer I have no way to see what is being downloaded or by what.

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    10 months later and no good answers; I conclude iOS has no way for you to inspect what is being downloaded in the background. The answers I've gotten so far have been "we guess it's iCloud backups using the network". It's not a bad guess, but it happens to be wrong in my case.
    – Nelson
    Commented Feb 11, 2016 at 15:36

3 Answers 3


Do you have iCloud Drive and/or iCloud backups enabled? If so, that's what it's probably doing. You may also want to check which apps you have enabled to refresh in the background. See: Settings > General > Background App Refresh


About once a week when I plug my phone in and it's on WiFi I find it's suddenly downloading hundreds of megabytes of data.

That sounds to me like it's just doing an iCloud backup, since those are the conditions under which a backup will run.

If you go to Settings > iCloud > Backup, check if iCloud Backup is enabled. If so, see if the date and time of the last backup correlates with when you last noticed that data usage. Or trigger a backup manually and see if it makes the same connections that you saw previously.

Also, go to Settings > Safari and see if Fraudulent Website Warning is enabled. I believe iOS periodically downloads updates to the list of fraudulent sites when plugged in and on wifi (although I can't currently find any documentation on this).


Have you checked the app data usage under Mobile Data? That would indicate what apps are using the most data on your cellular connection. By process of elimination, you can uninstall the apps that use the most data on mobile and see if that affects the data use on Wi-Fi. It's a tedious, annoying solution, but it's the best method I can think of.

Do you have your iPhone set to sync data to iCloud over Wi-Fi? That might be a factor too…

  • Thanks for the help! Do you mean Settings / Cellular, the "Use Cellular Data for..." shows data usage. Unfortunately it only shows it for cellular usage; I'm trying to track WiFi usage.
    – Nelson
    Commented Apr 2, 2015 at 15:28

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