FullReader is a versatile e-book reader app that supports a wide range of file formats, including PDF, DjVu, ePub, and more. It also allows users to listen to audiobooks and work with documents on their smartphones and tablets. The app features a user-friendly interface with clear navigation and convenient layout of all options and tools. Users can choose between a classic light theme or a brand new black theme, which is energy efficient for AMOLED displays. The app also offers a file manager that allows users to scan device memory and find all supported file formats, search for books according to various criteria, and benefit from a full-featured toolset for operations with files.

FullReader offers a variety of features to enhance the reading experience. The app has a customizable toolbar that allows users to switch the tools and their position in the reading window according to their needs and preferences. It also has a reading aloud option with customizable parameters, such as TTS engine, speed and tone of reading, voice, and color of highlighting of the currently read text fragment. The app also has a built-in translator that supports 95 languages and does not require the installation of any additional dictionaries. Users can create colorful notes in the text highlighting the important fragments and make bookmarks on interesting pages. All notes are grouped by books and can be exported into a separate document.

FullReader offers optimal color schemes for the reading window so that users can enjoy their favorite e-books in different daytime. There is also an option allowing users to set automatic switch of modes. The app also has tap-zones that allow users to set quick access to certain options and tools of the e-reader app right during the reading process. FullReader supports audiobooks in MP3 format, allowing users to not only play audiobooks but also make bookmarks while playback, create their own playlists, and control the overall reading process. The app is entirely adapted and translated into popular worldwide languages, including Russian, Ukrainian, English, German, French, Spanish, Portuguese, Italian, and Vietnamese.

FullReader offers integration into Google Drive, Dropbox, and OneDrive, allowing users to save storage space on their smartphone or tablet and sync their books between several devices. The app also allows users to add their favorite online libraries and download necessary books directly without leaving the app. FullReader offers wide settings, which are divided into quick, advanced, and general. Brightness control option is represented in a form of widget that can be invoked right in the reading window. The app also has a section that contains detailed book info, tools for basic operations with the book, and allows users to edit and add new info.