APKS and XAPK files hold several APKs at once, so Android can't open them on its own. Pick where you are:
On a computer
No app to install, no permission to grant, and your file never leaves your computer — it goes straight down the cable.
This one needs a computer running Chrome or Edge, plus a USB cable. On the phone itself, a free installer app does the same job. Installer apps for the phone
On your phone
Any of these will do the job. No reason to prefer another? Take the first.
APK Mirror
Opens every bundle format, picks the right splits for your phone, and tells you why an install failed instead of just failing.
TarrySoft
Unpacks XAPK archives and drops game data in the folder Android expects. Ad-supported, but reliable at that one job.
Uptodown Technologies SL
Works both ways: installs bundles, and extracts the apps already on your phone back out to files you can keep.
sunilpaulmathew
Open source, and the only one here that lets you choose exactly which splits get installed.
Neither of those
For when the Play Store isn't available, a managed device blocks installer apps, or you'd rather not trust one.
Good to know
An APKS file is a bundle of split APKs — the base app plus separate pieces for your screen density, CPU, and language. It's how Google's Android App Bundle format is distributed outside the Play Store. XAPK wraps the same splits, plus any OBB game data, in one file. Both hold several APKs at once, which is why Android's stock installer won't open them and the tools on this page will.
APKS, XAPK, and ordinary APK files — over a cable here, or with any of the installer apps above.
Android 8 and newer grant that permission per app: Settings → Apps → Special app access → Install unknown apps, then allow your installer. Android 7 and older have a single “Unknown sources” switch in Security settings. Installing over a cable needs neither.
Play Protect scans sideloaded APKs and warns even on clean ones. Tap More details, then Install anyway — and only for files from a source you trust.
Its OBB expansion file has to sit in Android/obb/<package.name>/. A good installer app puts it there for you; if you unpacked the file by hand, move it yourself.
No. Download and install each new version yourself.
Company and school device policies can block sideloading outright, and no installer can override that.