Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
Lodgify - Easily create a mobile-friendly website for your vacation rental with a “Book Now” function. Manage reservations and availabilities efficiently, and instantly synchronize property information with listings on multiple external rental portals.
MakePlans - Online appointment booking - MakePlans
Hostaway - Hostaway helps you grow and manage your business with the help of advanced automations, marketing, communication and reporting tools.
Dudle - Dudle is an online scheduling application, which is free and open source.
Smoobu - The all-in-one vacation rental management software