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Ironclad CAPTCHA

Professional free CAPTCHA for your site
Even if you are Google

Ironclad CAPTCHA

Also available in form of:
WordPress plugin - Download
Dreamweaver plugin - Download

  • 3D objects based CAPTCHA – easy for even a kid, impossible for robot
  • 5 lines of code to integrate into your existing PHP or ASP.NET application
  • Completely free of charge
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Why should I use it?

Almost every web site on the Earth that contains some form to allow visitor register, login, or to submit some information, suffers from spam. There thousands of robot programs that surf the Internet and fill in the forms to promote their sites, post unsolicited advertising or even compromise web sites they visit.

If you own some forum, blog, social networking site or a site with registration/login procedure, you know that spam can easily kill every good project in the matter of days.

The most effective measure against spam is to require user pass some test, often called CAPTCHA (Completely Automated Public Turing Test to make Computer and Human Apart). In most cases user should enter some letters or numbers or words he sees on picture (which is screwed, crossed by lines, noised, etc.) to pass the test and then he'll be allowed to submit form.

Bad news: All conventional CAPTCHAs are aready CRACKED. There are programs that can recognize your current CAPTCHA with 80% accuracy which means that your site WILL be spammed anyway.

Even current Google and Yahoo CAPTCHAs are already cracked (this rumored to be impossible for a long time, but not today). Though there are programs that can recognize them only with 35% accuracy, it is still enough! It just means that robot will try three times in average before he succesfully submits his spam.


Why do you call your Ironclad CAPTCHA "unpenetrable"?

Because it is unpenetrable. Nobody can crack it today, and nobody probably will in next 10 years. Instead of asking user to enter letters and numbers (which even real human sometimes can't recognize, but computer already can!) we show him a picture with several primitive objects like teapots, keys, balls, and so on.

Ironclad CAPTCHA is rendered in realtime from 3D scene, where each object can be positioned, scaled, rotated and colored in random way. We then require user to count the number of three given types in the picture to pass the test.

This is the task that even a kid can accomplish! But not computer. In image where there are a lot of objects which can't be determined by their shape (because the shape can change dramatically when the object is scaled and rotated), by their color (different objects can have similar colors and several objects of one type can have different colors) and can't be segmentated (because objects can intersect, overlap, etc.) computer raises its virtual hands and gives up!

Wow! But can I use it for my site? Is it free? Is it reliable?

Absolutely! You can use it for free for any site, even if it is commercial and even if it is popular and has a lot of traffic - our capacities are high and we can handle almost any load and deliver Ironclad CAPTCHA to your site in any circumstances. Ironclad CAPTCHA is hosted on its own dedicated server in one of the main datacenters of New York.

When we say that you can use Ironclad CAPTCHA on any site, there are however some exceptions. We DO NOT accept sites with adult content, gambling, advocating terrorism and discrimination of any kind. If your site doesn't fall into one of these categories - you are welcome!

Will it overload my site/server? You talked something of 3D rendering...

No! All rendering is done on our side - on Ironclad CAPTCHA dedicated server. Your site receives final image only. All CAPTCHA verification procedures are also accomplished on our side.

Is it easy to embed it into my existing site/forum/script?

Sure! If you know PHP/ASP.NET a bit, it won't be a problem. After you register you'll get access to membership area where you can download our PHP/ASP.NET library, examples of implementation and ask our support for assistance. In fact, embedding Ironclad CAPTCHA into your site is as easy as 1-2-3!

By the way, you can use our perfect Dreamweaver extension which makes installation process even faster. Ironclad CAPTCHA Dreamweaver Insert Wizard will guide you through the whole process and automatically add needed HTML, PHP and CSS code to your web page.

If you use Wordpress, you can install Ironclad CAPTCHA into your site or blog in several clicks with Ironclad CAPTCHA WordPress Plugin.

To summarise, why Ironclad CAPTCHA is cool?

Here are the clues:

  • It is free
  • It can be installed on any site in 10 minutes or less
  • You can tune up its look and feel to match your site easily
  • It is very easy to pass it for human
  • It is unpenetrable by all modern web robots
  • It consists of 3D objects rendered in real time
  • Each object is positioned, scaled, rotated and colored in random way
  • There are additional objects that should not be counted, besides three types that should
  • Some objects intersect and overlap so computer can't divide them (but human easily can)
  • It is reliable and fast
  • It is multilingual
  • It can be completed both by mouse and keyboard
  • It comes with our free 24/7 support

I'm ready to start! What should I do?

Register here and then login into your membership area, where you will get your personal API key for your web site, PHP and ASP.NET library, instructions and examples of implementation and our priority support. Don't forget - everything is free! Start now.

Do you offer some additional services for Ironclad CAPTCHA?

Yes, we do offer some payable services. You can request us to remove our copyright line from the bottom of Ironclad CAPTCHA. This option costs money. Please contact us to request quotes. While we provide basic installation help and troubleshooting for free, we can also install Ironclad CAPTCHA on your site for you. This will cost $75 per hour. Please contact us if interested.

Ironclad CAPTCHA screenshot 1
Ironclad CAPTCHA screenshot 2
Ironclad CAPTCHA screenshot 3
Ironclad CAPTCHA screenshot 4
Ironclad CAPTCHA screenshot 5
Ironclad CAPTCHA screenshot 6

Here you can watch Ironclad CAPTCHA in work.

Post your comment
Robert Boisvert (7 Aug 2008, 20:09)

This looks like a great extension.

Randi (19 Aug 2008, 10:31)

Do not expect immediate results for free. I am still waiting after two days for code.

Admin (29 Sep 2008, 04:49)

Registration process is now revised - you can use Ironclad CAPTCHA immediately after registration, without waiting for confirmation code.

Suneeth (31 Jul 2009, 11:00)

This looks interesting

Fred (5 Aug 2009, 13:56)

Has anyone got this working in Joomla 1.5.+? I can't figure out which .php files to place the two main code snippets into...

Jack (19 Aug 2009, 04:45)

Looks interesting, I just have four questions:

1. Are there implementation configurations which can allow me to change the size, layout of the interface?

2. Does this use cookies? ie - will visitors to my site need to have their browsers configured to accept third-party cookies?

3. I run a site where visitors will frequently want to submit a form multiple times daily. Providing they can pass the test every time, is there any limit on how often they can submit?

4. Is there support for different languages, or will the questions and instructions always be in english?

Support Staff (19 Aug 2009, 12:23)

Reply to Jack.

1) Currently no - you can't change size and laout of the interface, you can change its appearance only.

2) Captcha doesn't need or use cookies.

3) There are no limits on usage as of now.

4) We have no multilingual support right now, but this is something we are going to add very soon. I you want to participate - you can translate the interface into the language of your choice and we'll implement this quickly.

Christine (10 Nov 2009, 09:34)

I'm a website developer novice and I was able to get this integrated into 8 different .shtml forms with just the online help in a little over an hour. The examples helped a lot.

I sent an email with a couple of questions about customization after it was installed and received a response within minutes. I changed the set of objects that can appear, the prompt that precedes the captcha area, and the background color.

Bing (29 Jan 2010, 06:28)

I have installed this plugin and it works. The problem is where the visitor keyed in the WRONG count, the comment will still be sent to me. I received it in my wordpress comments box, but I did not get an email trigger to approve it.

That means that spammers cannot flood my website with spam comments, but they can flood my comments box right?

Peter (11 Feb 2010, 17:31)

Is there any way to use this with a ColdFusion form?

Support Staff (13 Feb 2010, 06:52)

to Peter:
At this time we don't have a ColdFusion version of Ironclad Captcha. But if you want you can help us with developing this. We will publish it at our website so it will be useful for other people.

Jim (15 Feb 2010, 23:55)

Nice. But what is to stop a spam bot from just trying to enter random numbers until it gets it right?

Support Staff (16 Feb 2010, 00:45)

to Jim:
After few wrong answers the Captcha will block any further attempts. So even if bot types a correct answer it will not be accepted. The real human passes the test with the first (or maximum the second) attempt.

dbrown7080 (2 Mar 2010, 01:24)

ive let dreamweaver install this and it does not work. the information is submitted even if you get the captcha wrong and with no warnings

Support Staff (2 Mar 2010, 09:14)

If it does not work then you did something wrong. Take a look at our examples of embedding Ironclad CAPTCHA in the control panel.

dbrown7080 (2 Mar 2010, 22:14)

i have tryed it with dreamweaver and done it manually and they both do the same thing.

dom (20 Apr 2010, 05:33)

Ironclad CAPTCHA appears aligned in the center. I want to align to the left. Is it possible?

Support Staff (20 Apr 2010, 09:01)

Put it into any container (div, table cell etc.) and set it's align. It should work.

dom (20 Apr 2010, 10:59)

I do not know how to do it (left align), please i need the code and where to put it.

Support Staff (21 Apr 2010, 02:35)

For example:
<div align="left">...</div>
Replace dots with Ironclad Captcha form (ironclad_captcha_get_form).

dom (21 Apr 2010, 05:45)

where it (ironclad_captcha_get_form)?
I think it does not work

i am sorry

Support Staff (21 Apr 2010, 09:52)

dom, it is easy for people who knows HTML. Please contact our support team because this is not the right place for discussion.

Adam (30 May 2010, 09:08)

Do you have a sound alternative for people with sight impairment?

Support Staff (1 Jun 2010, 01:40)

to Adam:
Currently we do not have audio alternative, but we are planning it in the nearest future.

Su Rahman (10 Aug 2010, 14:35)

Thank You, The Scripts is work at may website. I try to translate in to Indoenesia Language, i will send you the translate soon.

Support Staff (11 Aug 2010, 07:44)

to Su Rahman:
Please contact our support team to get source file for translating.

PcFunction (2 Oct 2010, 20:59)

It appears that Malwarebytes is still blocking your ip address ( I thought this got fixed! Maybe it was another malwarebytes update that caused it to get blocked again! I really like this service but it will not do any of us any good if it is not reliable.

I hope we can get this fixed!

Vince (10 Oct 2010, 12:36)

I am told from one of your staff that there is a full version of this software, if that is true I cannot find it?

Support Staff (10 Oct 2010, 14:12)

To Vince:

No, Ironclad CAPTCHA has only one version, and it is free and open for everybody. If you need some additional features, just let us know. We do our best to implement all suggestions.

David (6 Nov 2010, 14:15)

Do you know if this application works with modx?

Support Staff (9 Nov 2010, 05:15)

David: if you talking about MODx CMS then answer is yes, but you have to embed Captcha to this engine manually.

Agnes (6 Jan 2011, 16:54)

Hello - my site usesjava/jsp .

Can I integrate ironclad Captchas with my webpages


Support Staff (7 Jan 2011, 12:53)

Agnes, we don't have JSP libraries to work with our Captcha. Now it available in PHP and ASP only.

jennifer (17 Mar 2011, 14:08)

I'm getting an error with mine. I have no idea what I am doing wrong.

API key for this host is not valid:104:

and I don't see any information on your website for this error or for assistance. Help?

Support Staff (18 Mar 2011, 07:26)

One of the reasons «API key for this host is not valid» error is appearing is incorrect site URL, which entered in the control panel. Please note that in the most cases "" and "" is a different ones.

Opar (26 Oct 2011, 04:48)

Is there any limit on the number of Captcha requests per day/hour that can be supported for my site? What if it's a million a day - is it still free?
Do you have some sort of SLA you are committed to?

Vince (31 Oct 2011, 14:02)

Is it true that bots can still get your email address with this script?

reCAPTCHA hides your email address until the captcha is correct!

Support Staff (2 Nov 2011, 09:47)

Vice, it depends on how you have implemented CAPTCHA into your script. CAPTCHA does not affect any fields of your form, so you can hide any of them and do all what you need.

Support Staff (7 Nov 2011, 12:34)

Opar, you are limited 50 thousand queries per day. If your site does more, some delays and rejections can occur. About second question: we don't have any SLA for free version of Ironclad CAPTCHA. If you want to apply any certain agreements, the CAPTCHA will be a payment service.

Post your comment

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dom: Put it into any container (div, table cell etc.) and set it's align. It should work.

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