What is a .apk file? (APK)

An APK is an Android app installer. It is a signed ZIP bundle containing the app's code and resources, and it is what you install when you add an app outside the Play Store, so trust the source before you do.

What is a .apk file used for?

An APK packages everything an Android app needs: compiled code, images, and a manifest, all signed to prove who built it.

The Play Store installs APKs for you behind the scenes. Installing one manually, called sideloading, is useful but skips the store's safety checks.

Because it installs a running app, an APK from an unknown source carries the same risk as any executable.

How to open a .apk file

The .apk format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list. For a step-by-step walkthrough, see how to open a .apk file.

Windows

Android emulator
7-Zip (to inspect)

macOS

Android emulator
7-Zip (to inspect)

Linux

Android emulator
unzip (to inspect)

Web

Not applicable

How to convert a .apk file

You can convert a .apk file to Not convertible using a conversion tool or the export menu of an app that opens it.

.apk file signature (magic bytes)

Programs recognise a .apk file by the bytes at the start of the file, not by its name. These are the signatures for APK. For a full breakdown, see the APK file signature page.

Hex signature	Offset	Note
50 4B 03 04	0	ZIP header (APK is a signed ZIP)

See the full magic-numbers reference for every format.

Frequently asked questions

What is a .apk file?

How do I install an APK?

On Android, enable installing from unknown sources for your browser or file manager, then open the APK. Only do this for apps from trusted developers.

Related formats

Sources

Details on this page were checked against authoritative references:

Wikipedia: apk (file format)