Inventory Sync
Inventory sync is the process that keeps the number of rooms a property can sell the same on every channel that sells them. The property's system or channel manager pushes each new count out to every OTA and listing site, so a room that sells in one place closes everywhere else (availability (B_XML), Booking.com Connectivity developer docs) (What is a channel manager? All you need to know).
Last updated: November 2026
How inventory sync works
Searches for the term also cover stock in online stores; here, the inventory is rooms and nights.
The unit being synced is a room count per room type and date. On Booking.com, that figure is the number of rooms of a room type that the channel can sell, set alongside prices, closures and restrictions (availability (B_XML), Booking.com Connectivity developer docs).
Google Hotels uses an inventory message that sets the physical room inventory available to sell (ARI Overview, Google Hotel Center developer docs). Each new message replaces the earlier count for that room type and date, and a count of zero means the room type is sold out (Inventory count notification (OTA_HotelInvCountNotifRQ), Google Hotel Center XML reference).
Updates travel by push. Google asks partners to send messages whenever data changes in their system, so only new or changed data needs to go out (ARI Overview, Google Hotel Center developer docs). Booking.com gives the same instruction for availability: send only the changes (availability (B_XML), Booking.com Connectivity developer docs).
The loop closes when reservations come back. Booking.com partners collect reservations with a periodic pull, and Booking.com advises running it every 30 seconds or less (Troubleshooting overbookings, Booking.com Connectivity developer docs). Multi-channel inventory sync is that loop running for every channel at once, all fed from one count per room type and date.
Why inventory sync matters for hotel distribution
Double bookings happen in the gap between a booking coming in through one platform and the update reaching the others (How automated channel management prevents overbookings and keeps your rates right on every platform, Hospitality Net). Several of the causes Booking.com lists for overbookings are sync failures: system outages that stop availability from being updated, incorrect auto-replenishment of canceled reservations or room nights, late requests to close availability, and rates that are not mapped correctly for ARI updates (Troubleshooting overbookings, Booking.com Connectivity developer docs).
Short-term rentals that connect channels through calendar links work on a slower clock. Airbnb pulls in connected calendars automatically every 3 hours; a host can press Refresh, although Airbnb can only request updates from the other site so many times (Sync your Airbnb calendar with other calendars, Airbnb Help Center). Nights booked on another site's calendar are blocked on Airbnb automatically, and Airbnb imports up to 2 years of data, but nights a host blocks on another calendar may or may not be blocked on Airbnb (Sync your Airbnb calendar with other calendars, Airbnb Help Center).
Inventory sync compared with a channel manager, ARI updates and iCal sync
A channel manager is the software that runs the sync. ARI updates are the messages the counts travel in: Google defines ARI as a pricing delivery mode that controls nightly rates, availability and inventory (ARI Overview, Google Hotel Center developer docs). iCalendar, the format behind iCal sync, is an IETF standard for exchanging calendaring and scheduling information, built for calendars rather than for room counts and rates (RFC 5545: Internet Calendaring and Scheduling Core Object Specification (iCalendar), IETF).
| Inventory sync | Channel manager | ARI updates | iCal calendar sync | |
|---|---|---|---|---|
| What it is | The process of keeping room counts equal on every channel | The software that runs the sync | The messages that carry availability, rates and inventory | A calendar format shared by link |
| What moves | Rooms left to sell, per room type and date | Availability, rates and inventory out; reservations in when two-way | Nightly rates, availability and inventory | Availability only |
| Timing | Set by the connection it runs on | Pushes out to each channel | Sent whenever data changes | Scheduled pulls |
Frequently asked questions
What happens to the room count when a booking comes in?
What is the difference between one-way and two-way inventory sync?
How far ahead and how many rooms can an inventory update cover?
What is real time inventory sync?
Related terms
See all termsWhere Jetstream fits
Inventory sync works only when every channel draws on the same, current count. Jetstream builds an AI channel manager that connects a property to the channels where guests book and keeps rooms, rates and availability accurate on each one, managed from one place.