# Pre-populate form fields

Save time for clients by pre-populating their info on your invites. You can pre-populate every field on the invite page including name, email, and custom questions. 

Pre-populated fields are set by passing query parameters in the invite URL. Here's an example URL:

`https://zcal.co/i/12345678/?startDate=2026-01-01T18%3A30%3A00.000Z&timezone=America%2FLos_Angeles&name=John%20Smith&email=john@gmail.com&a0=Q1&a1=Q2&a2=Option+1&a3=Option+1,Option+2&a4=Option+1&a5=%2B15555555555&guests=adam@gmail.com,bob@gmail.com&locationIndex=1&smsPhone=%2B15555555555&duration=60`

###

### Add query parameters to your invite link

1\) Copy the link for the invite you want to share

2\)  If your link doesn’t already have a query parameter add "?" to the end of the link. If there's already a query parameter in your link, continue to step 4. 

3\) Add a property name (the field name) followed by the user's information (the field value). To add space between words, enter "%20". 

4\) To add variables to your link, enter "&" then add more query parameters per step 3.

Notes: 

* Invalid query parameters will be ignored.
* Query parameters can also be added to [embed](/share/embed.md) code

###

### Query parameter reference

Here is a list of the query parameters you can add to your invite link.

#### startDate

The date and ISO time to pre-fill.

Example: `startDate=2026-01-01T18%3A30%3A00.000Z`

#### timezone

The IANA timezone to pre-fill. 

Example: `timezone=America%2FLos_Angeles` 

#### name

The invitee's name.

Example: `name=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. Separate with commas if there are multiple guests.

Example: `guests=adam@gmail.com,bob@gmail.com`

#### locationIndex

If your invite has multiple location options, you can pre-select a location by index. Indices start from 0.

Example: `locationIndex=1`

#### duration

If your invite has multiple duration options, you can pre-select a duration by value.

Example: `duration=60`

#### smsPhone

If your invite has SMS reminders enabled, you can set a phone number starting with a valid country code.

Example:`smsPhone=%2B15555555555`

### UTM parameter forwarding

zcal will also forward UTM parameters in the URL to Zapier and webhooks:

**utm\_campaign**

This UTM tracking parameter is forwarded from the invite URL.

**utm\_source**

This UTM tracking parameter is forwarded from the invite URL.

**utm\_medium**

This UTM tracking parameter is forwarded from the invite URL.

**utm\_content**

This UTM tracking parameter is forwarded from the invite URL.

**utm\_term**

This UTM tracking parameter is 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/pre-populate-form-fields.md?ask=<question>
```

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.