On 28 September 2026, Booking.com stopped passing guest phone numbers to channel managers and property management systems. The number still exists in your Extranet and the Pulse app, but it no longer reaches the tools that message your guests. For a platform that runs guest communication on WhatsApp, that is not a problem with one message. It runs through the whole guest journey: the booking confirmation, the check-in reminder, the door code.
So we didn't patch one message. We went through how UpMarket handles a guest's phone number from the moment a booking arrives, and rebuilt guest messaging around two rules:
A guest's phone number only changes for a reason we can defend. And every message we can't deliver shows as failed, never as sent.
Here is what changed across the platform:
1. The first message always has a way through
The booking confirmation is the first message a guest gets from you, and until now it could only travel by WhatsApp or OTA messaging. When email is one of your delivery channels, the confirmation now uses it too. The email:
arrives in the guest's language: English, German, Spanish, French, Italian, Dutch or Portuguese
carries your branding and the property image
is sent as "{your name} via UpMarket", with replies coming straight to you
includes the same details as the WhatsApp message, with your chosen link as a button
It follows the delivery strategy you already use.
Under first available, email steps in when it is the first channel in your order that can reach the guest, for example when there is no valid phone number or a WhatsApp send fails.
Under all selected, every selected channel sends, ensuring that the guest always receives the messages via their available channels, and can use the one that is most convenient to them.
Booking.com guests are often reachable only through a relay address ending in @guest.booking.com or @partner.booking.com. Booking.com filters what passes through it, so these guests get a relay-safe version: plain text, with the link written out in full. Mark UpMarket as trusted in your Booking.com Extranet (our sending address as a trusted email, and upmarket.be and welcome.upmarket.cloud as trusted links) and it gets through. The Booking confirmation page shows you exactly what to add.
2. Every confirmation carries the right next step
A guest who has just booked is paying more attention to you than at any point until arrival. The new Booking confirmation page lets you attach one next step to the message:
Link | What the guest does | Best for |
Contact details link | Collects the guest's contact information | Bridging the gap between reservations where the guest's details are not available automatically, allowing for WhatsApp communication |
Online check-in | Starts their online check-in straight away | Properties that need ID, guest registration or a deposit settled before arrival |
Guest app | Opens your guest app for their booking | Getting guests into your app early, so they find your information before they ask for it |
No link | Nothing yet | Keeping the first message simple and sending check-in later |
The link goes out on every channel: a closing sentence on WhatsApp and OTA messages, a button in the email. If it doesn't apply to a booking, because the guest app is off for that property or the guest has already checked in online, the confirmation goes out without it rather than with a dead link. Every account starts on Guest app, so for properties where the guest app is off, nothing changes until you choose.
3. Guests without a phone number are asked for one
This is the part that bridges the Booking.com gap. Switch on Send them the contact details link instead, and every guest whose booking has no valid phone number gets a different next step: a contact details link that asks for their number.
It is a pre-check-in, not a check-in. The guest goes through four short screens (Welcome, Email, Details, Done), in under a minute and with no documents. Booking.com, Airbnb and Expedia relay addresses are refused, so you get a real email, and the phone number is checked with the same rules we apply to numbers from your PMS.
Submitting it saves the guest's email, phone and privacy consent, and nothing else. It doesn't complete online check-in, register the guest with the authorities, issue door codes or change the booking. From then on:
their number becomes the one we message: if WhatsApp is one of your channels, the next automated message goes there
online check-in starts pre-filled with their email and phone
The toggle is off by default. While it is off, the Booking confirmation page shows how many upcoming bookings have no valid phone number. You can also send the link yourself: every property and booking now has a Copy contact details link action.
4. Failures are visible, not silent
The worst message is not one that fails. It is one that fails while the screen says "sent". Across the platform:
WhatsApp is used only when it can deliver: the guest's number is valid and your WhatsApp number can send. Otherwise UpMarket moves on to your next channel
A message that can't be delivered is marked as failed in the Comms Hub, and you get a failure alert, instead of it disappearing
A reply you write that can't go by WhatsApp is stopped up front, so you know straight away
Resending a failed message really resends it, to the latest number on the booking
Check-in instructions that fail on WhatsApp show as failed on the booking, with Send now
Automated messages with no channel available yet are retried until their latest send time, instead of being marked as sent
How to set it up
Step 1 — Open the Booking confirmation page. Go to Automated Guest Messages and click Customise on the booking confirmation row.
Step 2 — Check how it is delivered. The Delivered by section shows your channels and strategy from Delivery Channels. Make sure email is on the list.
Step 3 — Allowlist UpMarket in Booking.com. The page shows what to add as trusted in your Booking.com Extranet.
Step 4 — Choose the link. Pick Online check-in, Guest app or No link.
Step 5 — Switch on the contact details link. Turn on Send them the contact details link instead for guests without a valid phone number.
Step 6 — Save your changes.
What to check in your settings
Add email to your delivery channels, after WhatsApp, so it catches every guest WhatsApp can't reach
Allowlist UpMarket in your Booking.com Extranet before your next Booking.com reservation arrives
Switch on the contact details link for guests without a phone. It is off by default
Correct changed numbers in the Comms Hub, not only in your PMS
Keep an eye on failed messages in the Comms Hub. They now show, so they can be resent
Common questions
Do I need to do anything for email confirmations to start?
If the booking confirmation is on and email is already one of your channels, no. It goes out by email as soon as the update is live in your account.
Will guests get the confirmation twice?
Not on the same channel. Under first available, they get one in total; under all selected, one on each selected channel, even when your PMS re-syncs the booking.
Does the contact details link check the guest in?
No. It saves their email, phone and consent, and nothing else. Online check-in function exactly how it already does.
Reaching every guest, without new work
Most of this needs nothing from you: confirmations find a channel, numbers stay put, and failures tell you. Two settings do the rest, email delivery and the contact details link, and Booking.com's change stops being a gap in your guest journey. Pair it with one inbox for every channel and no guest falls between WhatsApp, email and the Booking.com chat.
If you are evaluating guest messaging tools, ask each vendor what happens to a Booking.com guest with no phone number, and what their screen shows when a WhatsApp message fails.
Contact us to book a demo to see how UpMarket answers both.