What is an APK?
An APK (Android Package Kit) is the file format used by Google for their Android operating system to distribute and install mobile apps. Basically, an APK is an app. Most Android users aren’t aware what APKs are since Android devices handle app installation in the background.
Downloading APKs from online sites provide a workaround for users who aren’t able to download an app through the Google Play Store for whatever reason. However, users should be very careful about downloading stolen, pirated, or even malware-infected APKs. Manually installing apps using APKs is called sideloading. Sideloading gives users the ability to install apps ahead of release or downgrade apps to an older version.