Heart is in is a free iPhone app designed for couples to express their love and affection towards each other. The app allows users to send hearts to their favorite person, creating a special connection between partners.

The concept of the app is simple yet meaningful. Users are given only one heart, which they can send to their partner. However, if the partner does not send a heart back, it disappears. This adds an element of anticipation and encourages both partners to reciprocate their love.

One of the notable features of Heart is in is the ability to customize the appearance of the heart. The size and color of the heart change depending on the number of hearts exchanged between partners, making it a visual representation of their love.

To get started with Heart is in, users need to download the app and share an invitation code with their partner. Once connected, they can easily send hearts to each other by clicking on the heart mark within the app.

It's worth mentioning that Heart is in also offers Twitter integration, allowing users to share their love with a wider audience if they choose to do so. The app requires iOS 8.0 or later, ensuring compatibility with a wide range of devices.

Overall, Heart is in is a simple and charming app that helps couples stay connected and express their love in a unique way. With its intuitive interface and meaningful concept, it provides a delightful experience for couples looking to strengthen their bond.