Crveno Slovo is a user-friendly Orthodox calendar application designed for Android devices. It provides quick access to daily religious observances, including holidays, saints, and fasting types, with a clear display of red and black letters. Users can set personalized notifications to receive alerts three, two, or one day in advance, or on the day itself, tailored to their preferred timing. Additionally, the app includes an integrated Wikipedia feature that allows users to read articles about saints and holidays without leaving the app.

The application also offers a brief overview of important dates and liturgical periods, along with smart widgets that adjust colors based on church letters and chosen themes, displaying daily guidelines. A dedicated Prayer Book screen provides easy access to essential prayers, while special screens for Slava and greetings facilitate quick information retrieval and message sharing. With a clean and fast interface, Crveno Slovo ensures a straightforward user experience without the need for registration.