Calendar and bookings
For the hotel, the guest house, the studio renting by the hour: the stays of the Rooms module and outside calendars.
iCal: Booking.com, Airbnb, Vrbo
Every platform publishes a listing's bookings as an iCal calendar (an .ics address) and accepts importing one. It is the channel of properties without a channel manager, and Hela does it both ways.
Your rooms to the platform. Integrations → Booking.com · Airbnb (iCal) shows one iCal address per room. Paste it into Booking.com (Calendar → Sync calendars → Import) or Airbnb (Availability → Calendar sync → Import): stays reserved and in house in Hela block the dates on the platform. The address carries a signature; it reads without an account but cannot be guessed.
The platform to your rooms. In Booking.com (Export calendar) or Airbnb (Export), copy the listing's .ics address and paste it into the connector's Feeds to import setting, one line per room: <room id> = <.ics address>. Every hour Hela reads each feed and creates a reserved stay per new event, named as the platform names it ("Reserved", or the guest's name on Airbnb), from arrival to departure. An event already seen is not recreated.
The format carries neither price nor guest: payment happens on arrival, in Hela, as for a booking taken by phone.
Google Calendar
Integrations → Google Calendar → Continue with Google: every stay becomes an all-day event — "12 — Marie Kabila", from arrival to departure — in the chosen calendar (primary, or the id of a calendar shared with the team). Written on every arrival and departure, and once an hour for upcoming bookings; an extended stay updates its event rather than creating a second.
Whoever runs the server must have registered Hela with Google (GOOGLE_CLIENT_ID, the same as for Drive) with the Calendar API enabled.
Events
stay.checked_in and stay.checked_out are emitted on every arrival and departure, with the room, dates and guest: enough to tell housekeeping over Slack or WhatsApp, or to feed a sheet.