> For the complete documentation index, see [llms.txt](https://help.zcal.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.zcal.co/invite-settings/redirect-on-booking.md).

# 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.

<figure><img src="/files/60yzAFbsirDjrqxDa6N3" alt=""><figcaption></figcaption></figure>

2\) Enter the URL where you want to redirect invitees.

<figure><img src="/files/x1CUclQdg1d8LErWCPiq" alt=""><figcaption></figcaption></figure>

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.&#x20;

Example: `timezone=America%2FLos_Angeles`&#x20;

#### 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.