Sometimes in life things that seem sensible in theory don’t always work out in practice.

Communism and Captcha images are two obvious examples, and it’s the latter that I wish to focus on in this post.

Captcha is designed to be an effective way of validating things like applications, purchases and comments. Basically any online form that a crook or spammer might try to trick for personal gain.

Unfortunately it can also harm the user experience by causing untold frustration for people trying to decipher the random jumble of letters and symbols.

So here are six different alternatives to the dreaded Captcha images.

And by the way, I’m fully aware that I’m on shaky ground here bearing in mind our own process for posting blog comments, and this is something we’re looking to improve. 

Sadly, some form of comment protection is necessary given the volume of spam targeted at this blog. 

I am, however, interested in hearing from people with other suggestions or case studies on how they reduced spam comments….

Use a checkbox

One method of beating spammers without annoying users is to replace the Captcha with a simple checkbox.

This can be created using client-side JavaScript, meaning spambots won’t be able to tick the box as it’s only displayed to users on the client-side.

Example taken from UX Movement

This is clearly easier for users to complete, thereby improving the UX.

There is obviously an issue if users have disabled JavaScript, but you potentially can get around this by asking users to turn on JS before they fill in the form.

The honeypot

This solution is far from perfect, but it is a potential alternative to Captcha nonetheless. A honeypot involves creating a field that needs to be left blank in order for the form to be successfully submitted.

The form is hidden from genuine users through CSS, however spambots should still see it and fill it in.

Unfortunately users that browse the web with CSS disabled will also see the form and fill it in. This will obviously cause confusion as it’s unusual to be asked to leave a field blank when filling in a form.

Furthermore, some spambots are able to avoid honeypots by identifying common names for the text field. This means that the form has to have an unusual or misleading name, which will also dupe some genuine users.

A simple maths question

As an alternative to random words and numbers you could ask users to solve a simple maths problem, such as “what’s 1 + 1?”

It’s safe to assume that most people will be able to get the answer correct, however spammers are also wise to this tactic and can get around it.

Set time limits

Real users take a few moments to read all the information and fill in the blanks, however robots can fill it all in almost instantaneously.

By setting a low minimum time limit for page submissions sites can catch out spambots without any impact on genuine users. 

Unfortunately some spammers will be wise to this trick and find a way around it, but it will at least catch out some unwanted visitors.

Run checks for spammy content

Many of the spammers trying to get their comments published on the Econsultancy blog follow the same pattern.

In general the comments will either include a link to some random website – in fact they often include tens of links – or they’re trying to flog drugs such as tramadol or zanex.

By working out common trends and features of spam comments we’re able to blacklist certain words and phrases so they don’t make it past the spam filter.

This obviously isn’t going to catch all spambots, but it’s a useful tool in the war on spammers.

Interactive games

Are You A Human is an interesting service that requires the user to complete an interactive game before they are able to submit a form.

It works just by clicking and dragging objects, which is certainly more fun than asking people to identify a Captcha image.