ARI (availability, rates and inventory)

The three data types a property pushes out to every channel it sells on: how many units are available, what they cost, and what inventory exists to sell in the first place.

ARI is the payload in almost every PMS-to-channel connection. When a guest books on an OTA, the booking comes back in and the PMS sends a fresh ARI message out so the next channel sees the reduced availability. When that loop breaks, you get overbookings on one side and empty nights on the other.

Why it matters in practice

• Push frequency sets your exposure. A connection that syncs every 15 minutes leaves a 15 minute window in which two channels can sell the same room.
• Rates travel with restrictions. Minimum stay, closed to arrival and release periods usually move in the same ARI message, so a mapping error affects more than price.
• Not every connection carries everything. Some channel connections accept availability and rates but not the full restriction set, which is where rate parity complaints often start.

Marketplaces and distribution switches such as Shiji Switch or a channel manager sit in the middle of this traffic, normalising one property's ARI into the format each channel expects.

See also [[channel-manager]], [[rate-parity]], [[two-way-sync]].