Peeriod is a lifestyle application designed for iPhone users, developed by Tzu Han Kuan. It serves as a menstrual period tracker that enables users to conveniently record their menstrual cycles. The app also offers the functionality to be used collaboratively with intimate partners.

Peeriod boasts a user-friendly interface, making it easy and efficient to input and track menstrual data. It provides features such as cycle prediction, ovulation day estimation, and period reminders for both users and their partners. Additionally, the app allows for the sharing of menstrual calendars between partners, facilitating synchronized tracking for those planning to conceive or avoid pregnancy.