NOTE: While the below method still works as of March 2019, we have released a direct integration within OptimizePress 2 for the latest version of Google reCaptcha, and would suggest following our guide on integrating with Google reCaptcha version 3 as this direct integration will do a better job of protecting your forms from spam submissions
If you are seeing spam signups or spam email addresses/names in your email list, and would like to take further steps to prevent those, you may wish to install our anti spam plugin, an invisible reCaptcha for opt-in forms. Download the plugin here:
Setting up the Google reCaptcha plugin:
1. Install the plugin.
3. Fill out the form in Google Recaptcha page. Make sure to tick the box for the invisible recaptcha. 
4. Click your newly created label to access the API keys.
5. Copy the Site key and Secret key.
6. Go to OptimizePress >> Google ReCaptcha and paste your keys there. Save when done.
7. Finally, clear your element cache under to OptimizePress >> Support >> OptimizePress Cache. That’s it.
Note that your users only need to do the recaptcha once because the system has features to remember that a certain user is bot or not.
IMPORTANT: Please ensure when you are adding the site withing Google reCAPTCHA that you select “Invisible reCAPTCHA” and NOT “reCAPTCHA V2” otherwise this integration will not work and you’ll see an error message in the bottom right corner of your page.
At present, the Recaptcha system works with API integrated forms (where you have connected your autoresponder service via our API integrations). If you are using Custom Form integrations, this process will not work as standard.