Mein Blau is a productivity app designed for iPhone users, enabling them to monitor their mobile usage effectively. This app caters to both contract and prepaid customers, providing a comprehensive overview of data volume, minutes, and SMS consumption. Users can access tariff details, book options, and view their latest invoices and connection logs, all from a user-friendly interface. The app also offers a yearly overview of billing amounts for the past five years, ensuring users stay informed about their mobile expenses.

For prepaid customers, Mein Blau allows easy tracking of inclusive units and current balances, along with convenient options for recharging credits and changing tariffs. The app is designed to enhance the mobile experience by providing essential functionalities in one place. Users must register for the online service to utilize the app's features, which rely on the online services of Telefónica Germany.