reCAPTCHA reCAPTCHA is a free CAPTCHA service that helps to digitize books, newspapers and old time radio shows. About 200 million CAPTCHAs are solved by humans around the... Free Web No features added Add a feature 123 Like Mollom analyzes content, whereas reCAPTCHA performs checks on the visitor. Both are useful anti-spam techniques, but they aren't equivalent. smokris • Jul 2017 Disagree Agree
Akismet A spam filtering program that is free for personal use and you have to pay for corporate usage. Free Personal Web No features added Add a feature 6 Like
visualCaptcha A configurable captcha solution, focusing on accessibility & simplicity whilst maintaining security. Free Open Source Self-Hosted GitHub Mobile friendly Add a feature 2 Like Discontinued As from Dec 26, 2016: Please note visualCaptcha is no longer actively developed. It still works and should continue to, but it won't be improved by the initial team anymore. ... Source: https://github.com/emotionLoop/visualCaptcha/blob/master/README.md
CleanTalk Spam protection plugins for Joomla, WordPress, phpBB3, IP.Board, vBulletin and etc. Protection without CAPTCHA. Commercial Web No features added Add a feature 2 Like
Solve Media's CAPTCHA TYPE-IN™ Solve Media's CAPTCHA TYPE-IN ads are an easy plug-in solution that saves your users time while making your site more secure and more profitable. Instead of... Commercial Web No features added Add a feature 1 Like
UniqPin UniqPin is a free for non-commercial use service which destiny improve ability of interfaces detect a human or a computer operate with it. Surpassing a CAPTCHA... Free Personal Self-Hosted JavaScript PHP No features added Add a feature 3 Like
Sblam! Open-source implementation of server-side spam filtering of blog comments and forum posts. It's available as a free web service. It's open source, so you can... Free Open Source Linux Web No features added Add a feature 2 Like
Confident Captcha Confident Technologies provides free CAPTCHA security software called Confident CAPTCHA, a picture CAPTCHA that stops spam and bots. Download our free CAPTCHA security... Freemium Web Two factor authentication Add a feature 2 Like
FunCaptcha FunCaptcha is another Captcha software, but it has something more to it. No more "Write this into the box" captchas! These are Fun captchas!. Free Web No features added Add a feature 0 Like
Negative Captcha A plugin to make the process of creating a negative captcha in Rails much less painful. Free Open Source Self-Hosted No features added Add a feature 0 Like
