XAPK vs APKM vs APK vs APKS — the complete format guide

A plain APK (.apk) is a signed, installable Android package. It contains compiled code (DEX), resources, the AndroidManifest, and a signing block. Android's PackageInstaller can open any APK directly — that's the "Install unknown apps" flow you already know.

APK works for small or single-architecture apps. It becomes a bad fit once an app needs per-CPU binaries or language-specific resources — at that point a single APK has to ship every variant to every device, ballooning file size. That's why the split-APK formats below exist.

XAPK (.xapk) is APKPure's archive format. Under the hood it is a ZIP that contains a base APK, usually a set of Split APKs, and almost always the app's OBB data files. OBB is where heavy games store textures, audio and levels — a single game can pack 1 GB of OBB behind a 30 MB APK.

Because the stock installer doesn't copy OBB to /Android/obb/, installing a game from an XAPK manually means extracting the archive, copying files to the right path, and only then tapping the APK. A helper like X-Installer does that in one tap.

APKM (.apkm) is APKMirror's equivalent of an AAB split bundle. Internally it is a ZIP of one base APK plus configuration splits (per CPU ABI, per screen density, per language). APKMirror publishes APKM so the same download works on any device — the installer picks the right splits at install time.

An APKM typically has no OBB (APKMirror hosts games only when they fit the split model), so installing one is faster than an XAPK of the same app. You still need an installer that speaks the format; stock Android cannot open a multi-APK ZIP.

APKS (.apks) is the output format of SAI (Split APKs Installer) and the bundletool CLI that Google provides for inspecting Android App Bundles. Structurally it is the same idea as APKM: base APK + configuration splits in a ZIP, just with a different extension and metadata.

You'll see APKS when developers export an .aab as a sideloadable archive, or when someone re-packages a Play-delivered app with SAI. Any tool that accepts APKM usually accepts APKS — including X-Installer.