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How to protect your website forms from spam

11th September 2015

As the internet has grown and evolved, so too has the methods of scammers and illicit advertising. Spam is now ubiquitous throughout web and here is a run-down of some techniques that stop it from infecting our precious website forms.


One of the simplest methods of spam prevent is to give a simplistic math problem to validate whether a user is indeed human. However, this only really filters out the most menial of scripts/bots since the question is rendered on the form as standard text, meaning the spam bot can easily read it and solve it.


A step up from math is CAPTCHA, with its name derived from its full name, “Completely Automated Public Turing test to tell Computers and Humans Apart”. This is the process of procedurally generating an image with warped characters that the user then has to echo back to validate they are human. This technique relies on the fact that bots cannot as easily read characters or words in an image and variations often make it harder for bots by distorting the text.


This technique is more trap-like in nature, luring spam bots with a form field that they will unwittingly enter because they have been scripted to. Humans however would not fill this out since it would be hidden from their eyes (bots see webpages differently from us). This method gets its name from the metaphor of bears being attracted to honey – in this case the dummy field being the honey and the spam bot being the bear.

Specialist spam services

Many companies also offer their own methods of preventing spam on forms, often developing from the methods we mention but with their own twist. Here are some examples:


This company has developed a system for analysing the data that gets submitted in the form. They cross-check the data supplied with that of their own central database to determine whether the submission was indeed from a human.


Offered by Google, this technique offers a single no-mess-no-fuss checkbox for a simple, accessible easy to use validation for humans. They even channel the human effort of solving it into worthwhile and constructive causes.

In conclusion...

Being safe online can be as being safe in the real world. We hope that this information has given you a small insight into how people keep you – and your forms – safe from any online threats.