How to hide and prefill booking questions?

You may have come across a scenario where you want to pre-fill some information in the booking form for your clients and/or hide them. For example, you may want it to be hidden from the scheduler but shown on your Google Calendar after it is scheduled. Here's a step-by-step guide on how you can achieve this:

Step 1: Accessing the event-type settings

• Login to your Cal ID account
• Navigate to the event-type you wish to add the hidden booking field
• Click on advanced tab
• In the booking questions section, click on Add a question
• Fill up the question and take note of the identifier, you'll need it when prefilling it

• Click Add

Step 2: Hiding a booking question

• Notice the newly added booking question

• Disable the toggle now, if you want it to be hidden from the booking page. You can do that by clicking on the toggle.

• Click Save

Step 3: Pre-filling a booking question

If you want to pre-fill a certain question, you'll need to append a query parameter to the booking page URL.

The query parameter should match the identifier for the field you wish to pre-fill. As long as it is hidden, the booker shouldn't see that in the booking page, and you can send any custom information you want through this method.

For example:

Your Booking URL is https://cal.id/username/eventtype?overlayCalendar=true and you want to fix the value of Referral as John then your new URL is modified as

https://cal.id/username/eventtype?overlayCalendar=true&Referral=John

That's it.

Updated on: 19/01/2026