# Redirect on booking
### Add a redirect url to your invite link
1\) Edit your invite link. Under `Scheduling Options` turn on the `Redirect on booking` switch.
2\) Enter the URL where you want to redirect invitees.
3\) Save your invite. Invitees will now be redirected to your URL after booking events on this invite.
### Query parameter reference
zcal will append the following query string parameters to the redirect URL:
#### startDate
The event date and time in ISO format.
Example: `startDate=2026-01-01T18%3A30%3A00.000Z`
#### timezone
The invitee's IANA timezone.
Example: `timezone=America%2FLos_Angeles`
#### fullName
The invitee's full name.
Example: `fullName=John%20Doe`
#### email
The invitee's email.
Example: `email=john@gmail.com`
#### a\[custom question index]
Answer to a custom question. Each custom question has its own query parameter and question indices start from 0.
Freeform custom questions e.g. Short text can accept any string as a value
Example: `a0=Q1`
Multiple choice custom questions e.g. Dropdown can only accept strings that match one of the provided options.
Example: `a2=Option+1`
Checkbox custom questions can accept multiple comma-separated string values, all of which must match the provided options.
Example: `a3=Option+1,Option+2`
Phone number custom question responses must start with a valid country code.
Example: `a5=%2B15555555555`
#### guests
Guest emails.
Example: `guests=adam@gmail.com,bob@gmail.com`
#### locationIndex
The index of the location options your invitee selected. Indices start from 0.
Example: `locationIndex=1`
#### duration
The event duration.
Example: `duration=60`
#### smsPhone
The invitee's SMS phone number.
Example:`smsPhone=%2B15555555555`
### UTM parameter forwarding
zcal will also append UTM parameters to the redirect URL:
**utm\_campaign**
UTM tracking parameters are forwarded from the invite url.
**utm\_source**
UTM tracking parameters are forwarded from the invite url.
**utm\_medium**
UTM tracking parameters are forwarded from the invite url.
**utm\_content**
UTM tracking parameters are forwarded from the invite url.
**utm\_term**
UTM tracking parameters are forwarded from the invite url.
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# Agent Instructions: Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter:
```
GET https://help.zcal.co/invite-settings/redirect-on-booking.md?ask=
```
The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
