bozdoz

<a href="https://wordpress.org/plugins/jetpack/" rel="ugc">Jetpack</a> makes it easy to add contact forms to your WordPress site, but you may want a simple way to add a <a href="https://www.google.com/recaptcha/" rel="nofollow ugc">Google reCAPTCHA</a> to prevent spam. This plugin will manipulate the Jetpack <code>[contact-form]</code> shortcode to prepend the Google script, add a button, and parse the response.
This plugin allows both reCAPTCHA v2 and invisible reCAPTCHA (see screenshots and choose whatever works for you!).
Shoot me a question about it on Twitter: <a href="https://www.twitter.com/bozdoz/" rel="nofollow ugc">@bozdoz</a>.
This plugin is open source on <a href="https://github.com/bozdoz/wp-plugin-recaptcha-jetpack" rel="nofollow ugc">GitHub</a>!

reCAPTCHA Jetpack

A simple plugin that adds a Google reCAPTCHA to the Jetpack contact form. Requires the Jetpack plugin.

Brandon Kraft

Jetpack automatically disables its Open Graph tags when there’s a known plugin that already adds Open Graph tags, which is good. Sometimes, though, you might want to use Jetpack’s version instead. Even if you disable the tags in the conflicting plugin, Jetpack won’t add Open Graph tags without being told to do so.
This is great for when you want to use the awesome WP SEO by Yoast plugin or others like All-in-One SEO, but, for whatever reason, would like to use Jetpack’s OG tags instead.

Always Use Open Graph with Jetpack

Jetpack automatically disables its Open Graph tags when there's a known plugin that already adds Open Graph tags, which is good.

reCAPTCHA Jetpack vs Always Use Open Graph with Jetpack