10 Free CAPTCHA scripts and services for websites


This post proposes a list of ten exciting scripts and services you can use to protect spambots and ensure that only humans perform specific actions.

Free CAPTCHA scripts and services for websites



reCAPTCHA is a free service that helps prevent automated abuse of your site (such as comment spam or bogus registrations) by using a CAPTCHA to ensure that only humans perform specific actions.

Form-to-email script protected by Captcha

Form-to-email script

This form-to-email script is intended to collect data from an HTML form and send it to a specified email address using a CAPTCHA script to stop spam. It works with any HTML form, and you can use it multiple times on your pages.



OpenCaptcha is a simple web service that requires no unique configurations or modules. Basic installation is cut-and-paste and requires no ability to program image manipulation scripts. New fonts, image algorithms, and distortions are applied weekly. Captchas remain the most effective, universal method of preventing automated spam currently available on the web. While services like Akismet and linksleeve provide valuable protection, they are dependent upon widespread adoption to be successful.



ProtectWebForm is a service to add CAPTCHA images and audio files to your website. You have to create an account, generate your CAPTCHA type with all the desired parameters, and include it on your web pages. You can also use it on your WordPress template with this plugin.

WP Captcha-Free

WP Captcha-Free blocks comment spam using a combination of time-based hash (a.k.a. Time-Based Tokens, TBT) and JavaScript (AJAX). When a comment is posted, the plugin validates a hash based on time (and other parameters). Comments posted via automated means will not have a hash or have an expired hash and will be rejected. Unlike using a captcha, this does not place any burden on the commenter.



Securimage is an open-source, free PHP CAPTCHA script for generating complex images and CAPTCHA codes to protect forms from spam and abuse. It can be easily added to existing forms on your website to protect you from spambots.



Cryptographp is a PHP script for generating captchas. Cryptographp limits the robots bombarding spams and automating the forms: spaces members subscriptions, guestbooks, forums. This script is free and does not use any database. It is compatible with PHP >= 4.3.0



WebSpamProtect allows you to instantly add verification image (CAPTCHA) to your website and protect your forms against spam robots. Our system requires that you install a small piece of code onto your web page to protect your web form. Our code requires that your website support PHP, Perl, ASP, or ASP.NET.


ASP module captcha

CaptchasDotNet.asp. allows you to instantly add verification image (CAPTCHA) to your website and protect your forms against spam robots. In general, the process of using CAPTCHA can be divided into two stages. First, you have to query the user for the CAPTCHA on that page. You also usually let the user input the data, which has to be protected, e.g., blog entries.


ASP module captcha
captchas.net provides CAPTCHA images and audio files you can use in HTML forms. Your web pages have to be generated dynamically in any programming language PHP, ASP, Perl, Python, JSP, Ruby.

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