From a user perspective, disposable email registrations feel like a smart option. For app makers, though, they often lead to fraud, spam, abuse and other problems that muddy user data and sour customer experience.

Disposable reverse lookup for email threats are free to use and self-destruct after a short period of time, which makes it difficult for businesses to trace a user’s identity for support, billing, or other reasons. Fraudsters, scammers, and cheapskates love using them to farm free trial accounts, hoard promo codes, or test attack vectors. They’re also a waste of your valuable list building efforts and can skew your deliverability warming.

What Is a Mobile Carrier Identification API and How Does It Work?

Blocking disposable email addresses is a great way to clean your lists and reduce fraud and spam while maintaining a positive reputation as a sender. Disposable email detection services like IPQualityScore can identify these risky emails during the sign up process and block or warn users before they become a liability.

The best way to detect disposable emails is by implementing an automated validation solution that checks the email address in real time with an API call before it’s used on your site. UserCheck, for example, maintains a list of known disposable email domains and can be easily integrated into pre-user registration flows to block registration for users who have an email address on a suspicious domain.

Aside from preventing fraud and spam, blocking disposable email addresses is a good idea for your users’ privacy. For example, disposable email addresses can be used to track people’s online activities and link them back to their identity – something many users prefer to avoid.