Carlos E. G. Barbosa

If your Blog allows new subscribers to register via the registration option at the Login page, this plugin may be useful to you. It includes a reCaptcha block to the register form, so you get rid of spambots. To use it you have to sign up for (free) public and private keys at <a href="https://www.google.com/recaptcha/admin#createsite" target="_blank" rel="nofollow ugc">reCAPTCHA API Signup Page</a>. Version 3 added extra security by querying antispam databases for known ip and email of spammers, so you get rid of them even if they break the reCaptcha challenge by solving it as real persons.

Skt NURCaptcha

If your Blog allows new subscribers to register via the registration option at the Login page, this plugin may be useful to you. It includes a reCaptcha block to the register form, so you get rid of spambots. To use it you have to sign up for (free) public and private keys at <a href="https://www.google.com/recaptcha/admin#createsite" target="_blank">reCAPTCHA API Signup Page</a>. Version 3 added extra security by querying antispam databases for known ip and email of spammers, so you get rid of them even if they break the reCaptcha challenge by solving it as real persons.

Patryk

Block SPAM without any type of CAPTCHA – plugin add “HoneyTrap” (and a few other tricks) for comment form to block SPAMbots.
Plugin add “HoneyTrap” for comment form to block SPAMbots. Most od SPAM bot fills all comment fields (especially marked as required). plugin also use a few other tricks to eliminate SPAM from spambots.
Work fine for all my and my client site 🙂
Plug will not stop people writing comments – to block this type of spam additionally install eg. Akismet or Antispam Bee.

PRyC WP: AntiSPAM (without CAPTCHA)

Block SPAM without any type of CAPTCHA - plugin add "HoneyTrap" (and a few other tricks) for comment form to block SPAMbots.

Skt NURCaptcha vs PRyC WP: AntiSPAM (without CAPTCHA)