How to add Google recaptcha to a custom form? I have a form I'm creating programmatically with a custom module, and I need to add the Google recaptcha to it. In the Google reCaptcha module's settings page (/admin/config/spam_protection/google_recaptcha/forms) I only see the login, register and comments forms and no way to add a custom form (like in the captcha module). 

I googled as well as looked in the Google Captcha module's files and API file and can't find any hooks or info on how I can add the captcha element to a custom form. Any pointers would be appreciated!
You can use recaptcha module (https://www.drupal.org/project/recaptcha)
and in captcha settings(admin/config/people/captcha) you can add your custom form's form_id and select the challenge type reCAPTCHA(from module recaptcha). This should work.