> ## 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.

# Enable Captcha on Booking Page

> Protect your Cal ID calendar from spam bots and malicious scripts by adding a Cloudflare Turnstile captcha challenge to your public booking page.

Add a captcha challenge to your public booking page to keep automated bots and malicious scripts from flooding your calendar with fake appointments.

In **Cal ID**, the **Enable captcha on Booking page** feature is a vital security layer designed to protect your calendar from automated spam bots and malicious booking scripts.

<Info>
  Captcha is bot protection for your booking page: it verifies that a real person — not an automated script — is submitting the booking, so scrapers and bots can't snatch slots or fill your schedule with junk.
</Info>

## Why use "Enable captcha on Booking page"?

* **Bot Mitigation:** Prevents automated bots from flooding your schedule with fake appointments, ensuring your availability is reserved for real clients.
* **Protect Public Links:** Essential for "Discovery Calls" or public booking links that are easily accessible to web scrapers.
* **Prevent "Denial of Service" on Slots:** Bots can be used to "snatch" every available slot in seconds to prevent others from booking. Captcha blocks these scripts.
* **Clean Data:** Keeps your dashboard and connected CRM free from junk data and "trash" leads.

## How to set it up

<Steps>
  <Step title="Log in to Cal ID">
    Log in to your [**Cal ID**](https://cal.id/home) account.
  </Step>

  <Step title="Go to Event Types">
    Select the specific event you want to protect.
  </Step>

  <Step title="Navigate to Advanced">
    Click on the **Advanced** tab in the top navigation bar.
  </Step>

  <Step title="Toggle Captcha">
    Locate the **Enable captcha on booking page** option and switch it to **ON**.

    <Frame>
      <img src="https://mintcdn.com/cal-id-docs/3fu9CIn5wG7tNW3N/images/event-types/captcha-1.png?fit=max&auto=format&n=3fu9CIn5wG7tNW3N&q=85&s=3b4e87f6a1ebe33360bf5ac6f31a5102" alt="Enabling the captcha toggle in the Advanced tab" width="1439" height="754" data-path="images/event-types/captcha-1.png" />
    </Frame>
  </Step>

  <Step title="Select Captcha Strength">
    Once enabled, a new dropdown field will appear labeled **Select captcha strength**. Choose the level that fits your needs:

    * **Low:** Minimal friction; only challenges highly suspicious traffic.
    * **Medium:** The standard balance between security and user experience.
    * **High:** Strict verification; more likely to present visual challenges (like selecting traffic lights) to all users.

    <Frame>
      <img src="https://mintcdn.com/cal-id-docs/3fu9CIn5wG7tNW3N/images/event-types/captcha-2.png?fit=max&auto=format&n=3fu9CIn5wG7tNW3N&q=85&s=3cff38e204da5475effc43172569f938" alt="Selecting the captcha strength from the dropdown" width="1439" height="754" data-path="images/event-types/captcha-2.png" />
    </Frame>
  </Step>

  <Step title="Save">
    Click the blue **Save** button at the top right.
  </Step>
</Steps>

## How it works for the booker

* **Frictionless Experience:** Cal ID uses advanced reCAPTCHA technology. For most users, the check happens silently in the background without them having to do anything.
* **Interactive Challenges:** If the guest's browser behavior appears "bot-like," the system will present a visual or audio challenge (e.g., "Select all crosswalks") that they must solve before clicking "Confirm Booking".
* **Strength Impact:** At **High** strength, the system is much more sensitive, which increases security but may cause slight delays for legitimate users.

<Note>
  If you are using **Requires booker email verification** alongside Captcha, your booking page will be extremely secure. However, keep in mind that every extra step (Captcha + Email Verification) adds "friction." For internal team links or private 1-on-1s, we recommend keeping these settings at **Medium** or **Low** to ensure a smooth booking flow.
</Note>


## Related topics

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