.APP File Extension

The Symbian OS is used by phones from Nokia, Sony Ericsson, Samsung, and FOMA.

APP files are used by gamers who enjoy playing and altering Wii U games on their computers. Since APP files contain pieces of a Wii U game to reduce file sizes, all the APP files need to be present in order to play the Wii U game.

Also, Wii U APP files are encrypted and must be decrypted before they can be opened and played. A Title Metadata .TMD file, which stores metadata and the title key for the APP game, is required in order to decrypt the APP file.

APP files are named according to the number of files to which the game data was split. The files start at 0 (00000000.app), then increase from there to 00000001.app, 00000002.app, etc.

The Nintendo Wii gave players access to an online marketplace called WiiWare, which they could use to download additional games and applications for their console. The Wii downloaded these games and applications as WAD files which, when installed, became new Nintendo Wii channels. Each WAD file included a handful of compressed APP archives, which contained files used to install and access the new channel.

Nintendo discontinued the WiiWare marketplace at the beginning of 2019. However, homebrew gamers and Wii emulator users still use WAD files and the APP files contained within them to install Wii games and other applications.

Typically, Nintendo Wii players should not open the APP files included within a WAD file. However, homebrew gamers and emulator users may wish to view or extract the files contained within a channel's APP archives. To do so, you can decompress the archive using a U8 decompression tool, such as U8 Tool or Sharpii.

Many Huawei smartphones, tablets, smartwatches, and smart TVs use the company's proprietary HarmonyOS operating system. HarmonyOS allows users to install compatible Android apps, packaged as .APK files, and HarmonyOS-specific apps, packaged as APP files. In Huawei's AppGallery, HarmonyOS-specific apps are often marked with the HMOS label, allowing users to distinguish HarmonyOS apps from Android apps.

Developers package HarmonyOS apps into APP files at the end of the app development and publishing process. Prior to being packaged in an APP file, the app's modules are saved as one or more HAP files. Developers typically perform their development and testing using HAP files, and they use APP files only to publish their finalized app to Huawei AppGallery.

How do I package a HarmonyOS app into an APP file?

To package a HarmonyOS app into an APP file in Huawei DevEco Studio:

1. Open your app development project in Huawei DevEco Studio.
2. Select Build → Build Hap(s)/APP(s) → Build APP(s)

DevEco Studio will then create a release sub-directory in your project's build directory. This sub-directory will contain your app's APP file(s).

APP files are not meant to be manually opened. Developers can use Huawei AppGallery Connect to upload their APP files and distribute them to users. Users can download and install APP-based HarmonyOS applications from Huawei AppGallery.