WallUp is an Android Social Wallpaper application to explore HD wallpapers and save them to your device. You can use images and photos to set the wallpaper as home and lock screens. You can build your own wallpaper app using this source code.
The WallUp application has a list of wallpapers by multiple categories and establishes a wallpaper that is updated daily. It allows you to choose wallpapers and turn it into a comprehensive offer for each user.
It has many features such as profile editing, reports comments, likes and comments of wallpapers, and much more. Its backend is from Parse Server and is hosted on back4ap.