Wifi per app monitoring on iPad

Are there any apps to can monitor iPad network usage per app?

What's going on is out of no where one of our iPads will start uploading to Amazon's datawarehouse. Even if I double-click the button and shut everything down, it still finishes it's "sync" -- whatever it's syncing.

The problem is we don't know what app is causing this or even why it's causing this. Nothing is set to backup within iCloud.

For instance, one of the servers we're uploading 100KB (yes, that's bytes): s3-us-west-2-w.amazonaws.com -- now keep in mind, 100KB is a fairly significant amount of data to be uploading and it's making us very nervous about what data is being sent to Amazon's storage cloud that some arbitrary user has.

All we have is the official Amazon app and the Kindle app but my iPad never does this upload action.

It does this for non-trivial amount of time (read: > 3 minutes) -- which is a considerable amount of data and makes gaming and web browsing less enjoyable (and by that I mean miserable).

Powering off the iPad entirely and powering back on the iPad resolves the issue for a few days, which is interesting in and of itself.

Thoughts? I'm very interested in actually resolving the situation than just blocking at the router but can not find an app that allows me to identify which app is drinking my bandwidth like it's vodka.

Edit 1: iPad is latest generation -- iPad Air 2 -- with WiFi only.

Edit 2: How do I know what'g going on? I have a RT-AC87U router that tells me. I know it's just his iPad and I know how much it's uploading and downloading and where that data is going. I would expect regular updates / downloads but uploading large quantities of data has us baffled as all he has are video's, manga, Kindle, etc. Backups are handled manually.

Edit 3: There's a few apps he got from the Apple store such as ComicGlass. I'm not particularly interested in enumerating all the other apps as if there's no way to identify what app is doing this we will wipe the app and iPad go from there. I'm let down that there's no real troubleshooting method to know what application is sending data, of some kind, to a location that we don't have control over that we haven't asked to back up -- and Apple doesn't provide troubleshooting tools to help locate rogue apps like this, so with that, I must confess defeat since no comments have offered more than a manual method of figuring this out.

s3-us-west-2-w.amazonaws.com

AWS in this domain name stands for Amazon Web Services, while S3 stands for:

Amazon S3 (Simple Storage Service) provides a fully redundant data storage infrastructure for storing and retrieving any amount of data, at any time, from anywhere on the Web.

US and West probably refer to the location of those servers. (I use Amazon's Glacier to backup some of my data to the cloud so I recognize this pattern)

This means your iPad is uploading data to Amazon's cloud servers, but it doesn't necessarily mean it's Amazon's apps, since many developers utilize AWS within their own apps for tracking, monitoring, hosting, and storage.

Proposed solutions:

I suggest either/both of the following, none of which are "perfect" solutions:

1. You're saying that no matter what you do, the data is still uploaded. This means that this app has "Background App Refresh" enabled. Go to Settings, General, Background App Refresh, and make a list of "prime suspects"¹, disable background app refresh for these apps one-by-one and see if the uploading stops after you disable the background uploading for this app. (The app would still be able to upload if you use it)

2. (This won't work if your iPad is WiFi only) iDevices actually provide you with stats on cellular data usage by app. Go to Settings, Cellular, and scroll down until you see a heading: "Use Cellular Data For". Now, take a couple of screenshots at different times, and see if the data usage increases for an app that you haven't used since you've last seen the uploading process.

^{1 Would be really helpful if you edit your question with this list as well.}