Honeypot (Spam Protection)
A hidden form field invisible to real visitors but visible to automated bots, used to silently catch and reject spam submissions.
A honeypot field sits in the form's HTML but is hidden with CSS, invisible to a human filling out the form normally, but detectable by simple bots that fill in every field they find. If that hidden field arrives non-empty, the submission is discarded as spam.
Its advantage over a CAPTCHA is that it asks nothing of real visitors: no puzzle to solve, no friction added to the form, so it never costs you a legitimate conversion the way a visible challenge occasionally does.
It catches unsophisticated bots but not all of them; more targeted spam attacks fill every field deliberately. Sites facing heavier abuse pair a honeypot with a visible challenge like CAPTCHA rather than relying on either alone.
See it in practice