Contact Form Redux uses Google’s reCAPTCHA v2, which tracks a visitor’s behavior while completing the contact form and requires an “I’m not a robot” checkbox to be checked in order to submit the contact form. If the visitor’s behavior is suspiciously bot-like, they will be required to correctly identify a set of images prior to submitting the contact form. Non-human users, such as automated scripts, are much less likely to be able to submit the form.
Step 1: Get Google reCAPTCHA v2 Keys
In order to use Google’s reCAPTCHA v2, you must first visit Google’s reCAPTHCA site and create a Google v2 site- and secret-key pair for your domain. (You will need a Google account in order to create the keys.)
To create the key set, use the “Register a New Site” form if you don’t already have v2 keys for your site.
Enter a user-friendly Label for your site. It can just be your domain name if you like.
Select reCAPTCHA v2 and Checkbox (the default).
Enter your domain name in the Domains box.
Check the checkbox to accept the Google reCAPTCHA terms of service.
Click the “Register” button to create your reCAPTCHA v2 key pair.
If this is the first set of keys you’ve created, the Keys Section of the page will already be expanded, displaying your Site and Secret keys. If not, scroll down to the “Adding reCAPTCHA to Your Site” section and click on “Keys” to expand it.
Copy the Site key, making sure you get the complete key, then, in a new tab of your browser, go to the Contact, Integration page of Contact Form Redux. Click the “Configure Keys” button on the Integration page, and enter both your Google reCAPTCHA v2 Site and Secret keys in the corresponding boxes, then click “Save.”
Step 2: Add reCAPTCHA to Your Contact Form
Use the reCAPTCHA toolbar button on the Edit Contact Form page for the contact form you want to edit to add a reCAPTCHA Tag to your form.
In most cases, the best place to insert the reCAPTCHA Tag is right before the Submit Tag.