Calendly is a popular online scheduling tool that simplifies the process of setting up meetings and appointments. It allows users to create customized availability slots for various types of events, such as one-on-one meetings, group events, or interviews. The tool integrates with several calendar applications such as Google Calendar, Microsoft Outlook, and iCloud, allowing users to sync their calendars and avoid double-booking. Calendly also sends automated reminders and confirmations to both the organizer and the participants.