Can I prefill the Microsoft Bookings form from the URL?

How many people want this#

This is one of the most requested Bookings features:

• A Microsoft Q&A thread from 2020 has 90+ "same question" votes, and a later one has 40+.
• Askers describe the same situations: sending a booking link from a CRM or email tool to a known contact, passing an applicant or member ID into a custom question, or moving someone from a signup form to booking without typing their details twice.
• On the Microsoft Feedback Portal, the idea Allow prefilling custom fields with URL parameters (July 2025) is open with about 65 votes, the second-highest shared Bookings request at the time of research.

What happens if you try#

Users who tried links such as https://outlook.office.com/book/YourBusiness@contoso.com/?Name=Paul&Email=paul@example.com got a Microsoft "Bad Request" page. Bookings pages have rejected other query strings in the same way (UTM tags and %20 in UTM values), so appending parameters can break a working link. See why UTM parameters break Bookings links.

RefID is different. Microsoft documents ?RefID=<campaign> on the booking page URL, restricted to letters, numbers, underscores and hyphens, and the value shows in the Tracking data column of the appointment export. It is meant for "which campaign sent this booking", and users have reported both Bad Request pages and blank tracking data with it since 2023. It can't hold a customer's name or email.

What you can do natively#

• Reduce what people type. Only ask the custom questions you need; customer email, phone, address and notes can be made optional (they can't be removed). See custom fields in Bookings.
• Skip steps with a service link. Link to the Service booking page URL so visitors don't have to pick the service (see linking to one service).
• Book on the customer's behalf. For known contacts, staff can create the appointment in the Bookings Calendar tab and Bookings sends the confirmation.
• Vote on the Feedback Portal idea linked above.

Doing this with BookingsXP#

The BookingsXP widget accepts name, email, phone and notes attributes and fills them into the booking form for you, so a logged-in area or a follow-up page can hand over details the visitor already gave you. The values are passed to the widget via postMessage rather than in a URL, so they don't end up in browser history, server logs or analytics. The booking is still created in Microsoft Bookings, and Microsoft still sends its usual confirmation. See the embed feature. BookingsXP is independent and not affiliated with or endorsed by Microsoft.

<script src="https://bookingsxp.com/embed/v1.js" async></script>
<bookingsxp-widget widget="w_8fk2m1qz"
  name="Paul Smith" email="paul@example.com"></bookingsxp-widget>