API (Application Programming Interface)
An API (Application Programming Interface) is a defined set of rules that lets one software system request data or actions from another. In hotel distribution, APIs connect property systems, channel managers, booking engines, OTAs and metasearch platforms so that rates, availability, reservations and content move between them without manual entry.
How it is used in hospitality
- Rates and availability (ARI): a channel manager or PMS pushes updates to an OTA through its API.
- Reservations: bookings are delivered to the property system, either by the supplier pushing them or by the hotel's system polling for new ones (see Push vs Pull Connectivity).
- Content: property descriptions, photos and amenities are sent or synchronised.
- Reporting and payments: performance data, commission statements and VCC details are retrieved programmatically.
Modern hospitality APIs are usually REST/JSON, although many legacy connections still use XML messages, often following OpenTravel Alliance schemas. Access is typically secured with keys or OAuth, and event notifications are often delivered with Webhooks.
Example
A hotel changes its weekend rate in its RMS. The RMS calls the PMS API, the PMS calls the channel manager API, and the channel manager sends the update to Booking.com, Expedia and the hotel's own booking engine, usually within seconds. Without APIs, each change would be entered by hand on every extranet.
Why it matters
- Speed and accuracy. Fast updates reduce overbookings and Rate Leakage.
- Scalability. Properties and chains can add channels without extra manual work.
- Vendor choice. Open, well-documented APIs reduce lock-in and make it easier to build a connected tech stack.
- Risk. Rate limits, outages and version changes can break connections, so monitoring and fallback processes matter.
Related
APIs form the foundation of the Connectivity Layer and Switch technologies. Standards bodies such as HTNG and OpenTravel try to make them interoperable.