> ## Documentation Index
> Fetch the complete documentation index at: https://cal.id/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Require/Exclude Email Domains (Booking Question)

> Use the Email booking question's validation rules in Cal ID to allow or block specific email domains so only approved bookers can complete a booking.

Control exactly who can book with you by using the validation rules built into the **Email** booking question in [**Cal ID**](https://cal.id/home). Automatically filter out personal accounts or limit bookings to specific professional organizations, so your calendar stays reserved for the right audience.

<Info>
  **Allow vs. block.** *Require* rules act as an allowlist — only the domains you list can book. *Exclude* rules act as a blocklist — the domains you list are turned away, and everyone else is allowed.
</Info>

## Why use domain filtering?

* **Filter out spam:** Block common personal email providers so you only speak with business prospects.
* **Internal use only:** Set up a link that only allows people with your company's domain to book.
* **Competitor blocking:** Prevent specific competitors from booking by excluding their known domains.

## How to set it up

<Steps>
  <Step title="Open Event Types">
    Log in to [**Cal ID**](https://cal.id/home) and navigate to the **Event Types** tab.
  </Step>

  <Step title="Edit your event type">
    Click **Edit** on the specific event type you want to restrict.
  </Step>

  <Step title="Find the Email address question">
    Scroll to the **Questions** section and find the **Email address** question.
  </Step>

  <Step title="Open the question settings">
    Click the **Edit** button next to that question to open the "Add a question" settings.

    <Frame>
      <img src="https://mintcdn.com/cal-id-docs/3fu9CIn5wG7tNW3N/images/event-types/email-domains-1.png?fit=max&auto=format&n=3fu9CIn5wG7tNW3N&q=85&s=b8d130acc94fddd86bc350c1a08233e5" alt="Editing the Email address booking question" width="1422" height="743" data-path="images/event-types/email-domains-1.png" />
    </Frame>
  </Step>

  <Step title="Configure your validation rules">
    * **Require emails that contain...:** Enter the specific domains you want to allow (e.g., `yourcompany.com`).
    * **Exclude emails that contain...:** Enter the domains you want to forbid (e.g., `gmail.com, hotmail.com`).

    <Frame>
      <img src="https://mintcdn.com/cal-id-docs/3fu9CIn5wG7tNW3N/images/event-types/email-domains-2.png?fit=max&auto=format&n=3fu9CIn5wG7tNW3N&q=85&s=45172ada8cebaba69d051fc015e0c8c4" alt="Configuring require and exclude email domain rules" width="1434" height="756" data-path="images/event-types/email-domains-2.png" />
    </Frame>
  </Step>

  <Step title="Save">
    Click **Save**.
  </Step>
</Steps>

## Booker experience & error messages

If a guest attempts to book with a restricted email address, the system blocks the submission and displays a specific error message when they click **Confirm**:

* **When excluded:** If you've blocked a domain (like a personal Gmail account), the guest sees:
  > **"Please enter a valid work email address"**
  <Frame>
    <img src="https://mintcdn.com/cal-id-docs/3fu9CIn5wG7tNW3N/images/event-types/email-domains-3.png?fit=max&auto=format&n=3fu9CIn5wG7tNW3N&q=85&s=dd8832d589f6ac09e114995ae29f7d18" alt="Error message shown when an excluded email domain is used" width="839" height="481" data-path="images/event-types/email-domains-3.png" />
  </Frame>
* **When required:** If you've limited the event to specific domains and the guest uses a different one, they see:
  > **"You are not allowed to book with this email domain. Please contact the owner of this link."**
  <Frame>
    <img src="https://mintcdn.com/cal-id-docs/3fu9CIn5wG7tNW3N/images/event-types/email-domains-4.png?fit=max&auto=format&n=3fu9CIn5wG7tNW3N&q=85&s=d7fbcea162828f02826555fbc96b6d5b" alt="Error message shown when a required email domain is not used" width="839" height="481" data-path="images/event-types/email-domains-4.png" />
  </Frame>

<Tip>
  **Professional prospecting:** For Sales Discovery calls, it's common practice to exclude `gmail.com`, `outlook.com`, and `yahoo.com`. This ensures you collect professional contact information, making it easier to research your prospects and maintain a high-quality lead list.
</Tip>


## Related topics

- [Verify Email on Booking Page before the Booking](/docs/event-types/booking-questions/verify-email.md)
- [Add Pre-Booking Questions for Events](/docs/event-types/booking-questions/pre-booking-questions.md)
- [Enable Captcha on Booking Page](/docs/event-types/booking-questions/captcha.md)
- [How to Disable Adding Guests in Cal ID](/docs/event-types/booking-questions/disable-guests.md)