What is the difference between API and iCal integrations?

If a hospitality software use iCal links to sync to other websites, when a room or an apartment is booked and no longer available, the dates can be blocked on third party systems. Moreover, linking to OTAs using iCal links may mean that availability is only updated a few times a day. This can lead to double bookings as updates are not pushed out in real time, and moreover rates have to be set manually. On the other hand, API integrations allow rates and availability to be sent in almost real-time. Therefore, if your PMS supports API integrations to channels, your rates and availability are kept in sync between your website and all the channels and OTAs that have an API integration. Whenever a booking is made, whether from your website or a channel, the rest of the calendars are updated. However, if your PMS doesn’t have API integrations in place, this won’t happen instantly so you still face a risk of overbookings.