Originally created to protect users from spam, disposable emails have now become a source of sign-up abuse for software platforms, SaaS products, and email list-building campaigns. A disposable email is a temporary address meant for short-term use and then discarded. These emails are often used to avoid revealing the user's real identity during one-time registrations. They're frequently exploited by free riders who sign up multiple times using different disposable addresses to repeatedly access free trials, credits, or features—benefits intended for legitimate, first-time users.