A signup form to a bot is like an open vault to a safe.
3 Ways to Prevent Signup Form Abuse
1. Add CAPTCHA
By including a CAPTCHA or a reCAPTCHA on your signup form, it makes it difficult for bots to submit the form, preventing bot abuse from entering your system. Google makes it easy by utilizing a simple checkbox on their reCAPTCHA service as opposed to having to enter in those hard to read characters.
2. Add Honeypot Fields
When a bot is filling out a form, it’s simply reading the HTML fields. A honeypot field is one that is including the HTML but hidden from your actual real-life human visitors. So, if you receive a submission with this hidden or honeypot field filled out, you know it was done by a bot and can reject the data. Jenna Molby posted a tutorial on how to prevent spam using the honeypot technique on her blog for more information.
3. Require Confirmation
Just because the form was filled out, does it mean the person who owns that email address was the one who did it? Think about it – I can go to any website with a form, enter YOUR information, including email address, and sign you up for the most random email newsletters out there. Unless that form requires confirmation!
A confirmation message is an email that is delivered to the address on your signup form requiring the user to usually click a link to confirm opt-in status. If the intended recipient was the one who completed the form, there should be no issue with them clicking the link to confirm. This prevents fake signups or inbox abuse.