12 Essential Captcha Solutions

Posted in Tools | On 17th February 2010 | 15 Comments

Unfortunately in modern web design we now have to work around people abusing our contact forms and comment boxes, if left unprotected we can literally be overwhelmed by spam in a relatively short space of time.

Fortunately we now have Captchas (Completely Automated Public Turing test to tell Computers and Humans Apart) and we can add them to our scripts/sites and prevent or limit the amount of spam we receive.

There are a number of great free Captcha services and scripts available, and below are 12 that are free and do a great job of spam prevention.

Hosted Services

Captchator

Captchas

Open Captcha

Recaptcha

Spamerator

Text Disguise

VidoopCAPTCHA

WebSpamProtect

PHP Scripts

Cryptographp

Securimage

Wordpress Plugins

Simple CAPTCHA

reCAPTCHA WordPress Plugin

McBonio

McBonio is a full time web designer, blogger and general web lurker. He runs Tropica Web Design, which is a web agency based in Liverpool, UK. You can also catch McBonio at Twitter: @mcbonio

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15 Comments

  • Russell Bishop
    February 17, 2010

    Great selection of captcha methods here, but I can’t help but feel that the humble ‘honeypot’ solution should receive an honourable mention?

    It is, by far, the simplest method of capturing spam on any website, not only the idea behind it but also it’s implementation.

  • McBonio
    February 17, 2010

    Hey Rusell, the honeypot method isn’t bad, but when I have used it in the past it hasn’t been 100%.

    These new funky modern ninja bots must have some method of using javascripty things!

  • Jason A.
    February 17, 2010

    Great list, but I didn’t see any of the “question and answer” captchas, where the user is asked “What color is snow” or “what is 1+5″. I’ve had difficulty locating these myself lately. Any thoughts on these versus the image-based captchas?

  • McBonio
    February 17, 2010

    I think many of the Q&A and number captchas use javascript and bots can work a way around quite easily, php ones work better.

    Here is a free sum captcha for ASP: http://bit.ly/8qwaJN and a paid option in PHP ($6) http://bit.ly/cqXETc

  • cchana
    February 18, 2010

    recaptcha has always been a great solution and one that has reduced spam on various blogs i run to virtually 0!

  • Jim
    February 18, 2010

    You say Honeypots aren’t 100% effective, but then neither are captcha’s..

    captcha’s have been broken many times and are an absolute hinderence to the end user.

    captcha’s are bad, m’kay?

    http://www.w3.org/TR/turingtest/

  • McBonio
    February 18, 2010

    Totally right Jim, neither are 100% effective, but I feel Captchas stop a little more than Honeypots.

    Captchas can be broken, and thats one of the benefits of hosted options (such as recaptcha) as they constantly update and monitor their Captchas.

    For the end user that are a royal pain in the ass, but unfortunately they have a place as without them you could drown in spam, today so far I have had 88 spam comments which have been filtered! :)

  • Pat
    February 18, 2010

    One that should be included in this list is Mollom, which shows Captcha only when it detects that it is needed.

    http://www.mollom.com

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