What is an APK file?

What's inside an APK

Open one in any zip tool and you'll see: AndroidManifest.xml (declares permissions and components), classes.dex (compiled Java/Kotlin), resources.arsc (compiled resources), a res/ folder (images, layouts), a lib/ folder (native code), and a META-INF/ folder (signing info).

Why APKs are signed

Every APK is signed with a developer key. Android won't install an APK with a broken signature, and it won't let you upgrade an app to a build signed with a different key — that's why you can't sideload an update over a Play Store install.

AAB vs APK

Newer apps ship as Android App Bundles (AAB). The Play Store generates a per-device APK from the AAB. End users still get an APK; developers just stopped building one APK for everyone.

How to install one

Drag the APK onto a connected device with Andora, or run adb install <file>.apk. Either approach reads the manifest, verifies the signature, and installs.

Are APK files safe?

An APK is just a package format — no more dangerous than a .exe on Windows. Safety comes down to the source. APKs from the Google Play Store or a developer's official website are safe. APKs from random "mod" or mirror sites are not: they're a common vehicle for repackaged malware, where a trojan is bolted onto a legitimate app and re-signed. Two habits keep you safe — only download from sources you trust, and leave Google Play Protect enabled so Android scans sideloaded apps before they run.

Installing an APK from your PC

Installing from a computer is usually safer and faster than downloading APKs directly on the phone — you avoid sketchy mobile-browser redirects and can verify the file first. The two reliable routes are a drag-and-drop GUI or a single ADB command. Our step-by-step walkthrough covers both: how to install an APK on Android from a Windows PC.

Frequently asked questions

Can I open an APK on Windows? You can inspect it — an APK is a zip archive, so any archive tool will open it — but you can't run it. APKs are Android programs; to actually use one you install it onto an Android device.

Why won't my APK install? The usual causes are a signature conflict with an app that's already installed, a CPU-architecture mismatch, or a minimum-Android-version the file requires. See ADB install-failed error codes for the specific fix.

What's the difference between an APK and an app? The APK is the installer file — the package you download. The app is what exists on the device after that package is installed and registered with Android.

Is it legal to install APKs? The APK format itself is completely legal, and sideloading apps you own or that are offered for free is fine. Legality is about the app's licensing, not the file type.