Written by Mark Enrega on Friday, August 10, 2018

reCAPTCHA is a leading CAPTCHA service (that's "Completely Automated Public Turing test to tell Computers and Humans Apart") that is provided for free by our friends at Google, and it can be used on any web form on any website. CAPTCHAs are used to separate humans from bots and their purpose is to prevent bots from submitting forms, and to ensure that forms are submitted by human visitors. You've probably seen CAPTCHAs a million times on sign-up pages and on web forms across the internet. Often this is done by challenging the user to decipher words, letters or numbers, pick out objects in a grid of pictures, or just click a checkbox.

reCAPTCHA: Tough on Bots, Easy on Humans

We all know how annoying some CAPTCHAs can be. Sometimes the words, letters or numbers we have to enter into the CAPTCHA field can be pretty hard to read and it often takes us several goes to get it right - which means the user gets penalised with yet another thing that needs to be done before a form can be submitted. If the user fails to get it right, the form does not get submitted and a potential customer could be lost forever. reCAPTCHA has changed all this and made the CAPTCHA process as easy as possible for humans, whilst doing a great job at stopping bots.

reCAPTCHA has evolved over time, and the current version is very easy to use. Rather than having to decipher some obscure string of characters, the user is presented with a simple "I'm not a robot" checkbox. Clicking this box sets the wheels into motion and the reCAPTCHA system does its thing. If the system cannot identify you as a human, it then presents another layer of choices - often asking the user to make some choices from a grid of images; which, in theory, is something that only a human can do. What's even more cool is that reCAPTCHA provides an audio CAPTCHA option which is especially for people who are visually impaired.

reCAPTCHA in action

To see a working example, take a look at reCAPTCHA on our enquiry form.

Making reCAPTCHA invisible

Google is now taking things one step further by making reCAPTCHA invisible. The current version of reCAPTCHA is already very easy to use - just a simple "I'm not a robot" checkbox will get people through the web form on your website. The new version is even more simple, and it doesn't use a challenge or a checkbox. It works invisibly in the background, somehow, to identify bots from humans. Google doesn't go into much detail on how it works, only saying that the system uses "a combination of machine learning and advanced risk analysis that adapts to new and emerging threats." More detailed information on how the system works would probably also help bot-makers crack it, so don't expect details to pop up any time soon. Google have released the following video to explain how it all works.

When websites switch over to the invisible reCAPTCHA system, most users won't see a CAPTCHA at all, not even the "I'm not a robot" checkbox. If they are flagged as "suspicious" by the system, then it will display the usual challenges.

The development team at Enrega are working hard to integrate the invisible reCAPTCHA system into the websites we've built and we plan to use it exclusively in the future. Until then, the simple "I'm not a robot" checkbox version of reCAPTCHA is available for inclusion on your website now.

Want to know more about reCAPTCHA?

More information about this product can be found on the reCAPTCHA website. For the nerds, you might like to take a look at Google's technical documentation

(Photo courtesy of Google)