No Spam Contact Form: reCAPTCHA question?

Hi,

So I’m trying to get reCAPTCHA implemented on my site and I have a few questions and hopefully people in FCC is able to help me with.

  1. Am I required to have PHP to use it? Cause from Google site, it seems I need to use PHP to handle my POST request? Which seems to be a problem since I’m using https://github.com/dwyl/html-form-send-email-via-google-script-without-server to do my contact form
  2. From the given front end code, when I run it on my site, it gives a ERROR for site owner: Invalid domain for site key which I guess is expected since the site is running in my local directory (file:///Users/…/contact.html), so what should I do in order to locally test this out? Use MAMP?

Thanks