Apps similar to Invisible Anti-Spam & CAPTCHA include Cap Captcha, which is free and open source. Other options are reCAPTCHA, Private Captcha, ALTCHA and Procaptcha. You're spoiled for choice with Anti-Spam Tools like Invisible Anti-Spam & CAPTCHA: we list more than 25 alternatives for the web and self-hosting.
Anti-spam plugin blocks automatic spam in comments section. No captcha. Plugin is easy to use: just install it and it just works. Blocked comments can be stored in the Spam area if needed. This can be enabled/disabled via Settings page.
United States
SpamPatrol provides API and integrations that allow you to analyze messages submitted on your forms to see if they are spam or not. Instead of worrying about block lists, CAPTCHAs, honey pot fields, etc.
United States
MUTE silently blocks automated spam submitted through website contact forms — without CAPTCHA, without friction, and without any changes to your existing setup.
Japan
