TOSアプリ is a communication app developed by TOS テレビ大分, a terrestrial TV station in Oita prefecture, Japan. The app aims to bring viewers closer to TOS and make it more accessible to them. It provides several categories such as "Know," "Watch," "Apply/Send," and "Enjoy" to connect viewers with TOS. The app offers various features such as posting videos and messages, applying for giveaways and previews, and checking traffic information. In addition, it includes information on Oita Prefecture's news, weather, events, and programs. The app also features a stamp rally function, which allows users to participate in Jimota Villary 2021 and earn points. The accumulated points can be exchanged for TOS goods.

The app's "Make the program more fun!" feature allows users to send messages to TOS, which may reflect in the broadcast. The app provides articles on shops and events introduced in the program. The app is free and available on the Android platform. The app's goal is to bring TOS TV Oita closer to its viewers and make it more reliable and trustworthy.