Turnstile is a MODX Extra that allows you to incorporate CloudFlare's Turnstile Captcha into your MODX site.
Install via Package Management.
Sign up for a CloudFlare account. Within the CloudFlare dashboard, click on Turnstile and select "Add Your Site". You can then copy the Site Key and Secret Key into the Turnstile system settings in MODX.
Turnstile currently only works with FormIt. To use it, add the following to your FormIt call:
[[!FormIt?
&hooks=`tsFormItHook`
...
Within the body of your form, add the following snippet:
[[!tsRender]]
This will render the Turnstile Captcha. If the user fails the Captcha, the form will not be submitted.