Availability Calendar shows which dates are free and which are taken, on your own site. It suits holiday cottages, rental flats, guest rooms and wedding venues.
You mark booked dates in the app's dashboard. Click a date to mark it, click it again to free it, or shift-click to mark a whole stay. The calendar on your site changes at once. For stays, check-in and check-out days show as half days, so guests can see that a changeover Saturday still works for arriving. Venues and photographers can count whole days instead.
If you also rent through Airbnb, Vrbo or Booking.com, Premium reads their calendar export links (iCal) every two hours, so those bookings show up without being typed in twice. It only reads them and never changes anything there. Premium also gives you an export link of the dates you mark here, which those sites can import.
Visitors see free and taken days, never guest names. With Premium they can pick dates and send a request with their name, email and a message. It arrives in the dashboard and in your contacts, and you reply by email.
The free plan shows one calendar, this month and next, with a small credit link.