Key Maestro is a free iPhone app developed by Mariyam Mansur, designed to enhance your key signature recall and reinforce your understanding of the Circle of Fifths. Whether you are a singer, instrumentalist, or simply intrigued by music theory, Key Maestro offers a fun and engaging way to learn and memorize key signatures. The app features four exercises focusing on Major Sharps, Minor Sharps, Major Flats, and Minor Flats, with 12 questions in each round for daily practice.

Key Maestro's unique Circle-of-Fifths structure facilitates connections between musical concepts, while providing an instructional page during exercises. Additionally, users can access a piano screen to help derive key signatures themselves, all accompanied by delightful musical creatures to make the learning experience enjoyable.