App data and IndexedDB
[This article is for Windows 8.x and Windows Phone 8.x developers writing Windows Runtime apps. If you’re developing for Windows 10, see the latest documentation]
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Each app has a quota of 250MB. Among all apps on the device, the limit is 4% of the disk size or 20GB, whichever is smaller. For hard drives that are less than 30GB, the limit among all apps on the device is 375MB. Because of the overall quota among all apps, test your app to ensure it functions properly when it can store very little or even no data because other apps consume the overall quota. IndexedDB is primarily useful as a place to cache data from a web service for offline use.