https://api.beds24.com/json/getAvailabilities - JSON getAvailabilities can be used after collecting booking dates and room etc. from a guest to make a last minute live check of availability and price before confirming a booking in the OTA.
Webhooks can be setup at the menu Apps & Integrations > Webhooks to notify the OTA when inventory for a room type has changed. This can be used to make polls to HotelAvail for updated data in a timely and efficient manner.