Matt Keys

Anti-Spam solutions that require your users to fill out captcha’s are frustrating for actual humans, and not that great at stopping bots.
This solution works automatically without any user configuration, and puts no additional burden on your users. After activation this plugin will go to work stopping: comment spam, spam bot registration, and bbPress spam.
Key features:
<ul>
<li>Fully compatible with wordpress caching plugins or even more advanced server level caching solutions (like WP Engine uses).</li>
<li>Utilizes randomly generated and rotating token field name and token value, which stops more clever bots that might try caching the ‘solved’ field.</li>
<li>Anti-spam field is randomly placed within the form on page load to make it difficult for spammers to target the field.</li>
<li>Developer friendly with filters and actions</li>
<li>Lightweight, clean, and efficient solution to comment, registration, and bbPress spam</li>
<li>Uses native JavaScript to avoid jQuery dependancies</li>
</ul>
Requires JavaScript be enabled in client browser (Users will see a warning if JavaScript is disabled)

Advanced Invisible Anti-Spam

Block bots without annoying captchas. Cache friendly solution with rotating keys! Blocks comment, registration, and bbpress spam. Activate and done!

Minor

Simple Google reCAPTCHA will protect your WordPress! You have choice between default v2 Checkbox and v3 (like invisible reCAPTCHA).
No more spam comments and brute-force attacks against user accounts. Small plugin, only necessary code – no ads or tracking!
Google reCAPTCHA verification will be required only for not logged in users.
User, who newly setup the keys, will see (max for 10 days) emergency reCAPTCHA deactivate link – don’t need FTP access to disable Simple Google reCAPTCHA in case of emergency now.
<h4>What is protected with reCAPTCHA?</h4>
<ul>
<li>Login form</li>
<li>Registration form</li>
<li>Reset password form</li>
<li>Comment form</li>
<li>New password form</li>
</ul>
<h4>Thank you!</h4>
Thanks all of you, who are using this plugin, I really appreciate it!
If you write me (on support forum etc.), be patient, please. I work on this plugin in my free time, it’s only my hobby.

Simple Google reCAPTCHA

Simply protect your WordPress against spam comments and brute-force attacks thanks to Google reCAPTCHA v3 or v2 Checkbox for free and without ads!

Advanced Invisible Anti-Spam vs Simple Google reCAPTCHA