> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.cal.id/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Require/Exclude Email Domains (Booking Question)

In [Cal ID](https://cal.id/home), the **Email** booking question can validate domains — filtering out personal accounts or limiting bookings to specific organizations.

| Why use domain filtering

* **Filter spam:** block personal email providers so you only meet business prospects.
* **Internal only:** allow just your company's domain.
* **Block competitors:** exclude specific domains.

| Set it up

1. Open **Event Types** and click **Edit** on the event.
2. In the **Questions** section, find the **Email address** question and click **Edit**.

![](https://storage.crisp.chat/users/helpdesk/website/-/6/f/1/c/6f1c2c7b8034d000/image_1ifit3j.png =1177x615)

3. Set your rules:
* **Require emails that contain…** allowed domains (e.g., `yourcompany.com`).
* **Exclude emails that contain…** blocked domains (e.g., `gmail.com, hotmail.com`).

![](https://storage.crisp.chat/users/helpdesk/website/-/6/f/1/c/6f1c2c7b8034d000/image_5rn65c.png =1166x615)

4. Click **Save**.

| What the booker sees

* **Excluded domain:** *"Please enter a valid work email address."*

![](https://storage.crisp.chat/users/helpdesk/website/-/6/f/1/c/6f1c2c7b8034d000/image_uquf2g.png =1072x615)

* **Not in the required list:** *"You are not allowed to book with this email domain. Please contact the owner of this link."*

![](https://storage.crisp.chat/users/helpdesk/website/-/6/f/1/c/6f1c2c7b8034d000/image_wxujgj.png =1072x615)

| 💡 Tip

For sales discovery calls, excluding `gmail.com`, `outlook.com`, and `yahoo.com` keeps your leads professional and easy to research.