BotDetect PHP CAPTCHA

BotDetect™ prevents automated submissions of PHP forms using CAPTCHA images. The BotDetect Captcha PHP class generates and validates best-of-class Captcha images specifically designed to be out of reach of current computer vision and OCR technologies. The library provides an audio Captcha alternative as well, to keep PHP forms accessible to the blind and other people for whom reading the Captcha code could be a problem, enabling you to make WCAG and Section 508 compliant websites.

Why BotDetect PHP CAPTCHA?

BotDetect is unique among Captcha solutions in offering many Captcha image and sound styles. While each of them is easily comprehensible to human users, randomly using multiple Captcha generation algorithms makes the Captcha challenge practically impossible to pass automatically.

This approach to Captcha security is validated by the BotDetect track record: we have over 2500 paying customers and not one confirmed case of automated Captcha breaking by spammers.

WordPress CAPTCHA Plugin Released

BotDetect Captcha is now available for your WordPress websites!

Full support for all Android & iOS devices

BotDetect PHP CAPTCHA v3.0.Beta2 audio now works on Android and iOS devices. Unlike other Captchas, sounds are played directly on the form page, without opening the media player app.

The BotDetect PHP CAPTCHA Library

This high-security Captcha protection can be added to your PHP forms with a single line
(<?php require("botdetect.php"); ?>), and fully customized and randomized by editing the botdetect/CaptchaConfig.php file. The library also comes with several PHP code samples demonstrating how to integrate Captcha protection in various PHP usage scenarios, and how to use the many available Captcha features.

BotDetect PHP CAPTCHA Features

BotDetect PHP CAPTCHA Free Version

You can download BotDetect PHP CAPTCHA Library for free and use it immediately! Your PHP forms can be protected from spam (and bots in general) in minutes.

We offer basic email support for free to all BotDetect users. So if you need any assistance integrating BotDetect or have any questions or feedback, our Support department is at your disposal.

Once the BotDetect Captcha component has been integrated into your PHP website and you're satisfied with how it works, it's easy to upgrade your license if you need the extra features offered by commercial BotDetect versions.

BotDetect PHP CAPTCHA Free Download

BotDetect PHP CAPTCHA System Requirements

OS Server PHP

Supported Operating Systems:

  • Linux
  • Windows
  • Mac OS X

Supported Web Servers:

  • Apache 2.2+

Supported PHP Versions:

  • PHP 5.5.0+
  • PHP 5.4.0+
  • PHP 5.3.2+
  • PHP 5.2.1+

PHP installation must include libgd and mbstring support.


Please Note

BotDetect 3.0 PHP Captcha Library Beta2 is an in-progress port of BotDetect 3.0 Captcha, and we need you to guide our efforts towards a polished product. Please let us know if you encounter any bugs, implementation issues, or a usage scenario you would like to discuss.

BotDetect PHP Captcha v3.0.Beta2 now supports localized Captcha generation, using various Unicode character sets and downloadable multi-language captcha pronunciations.