Most disposable email blockers run the same public GitHub list. That list has .gov, .edu, Apple Hide My Email, Firefox Relay and uk.com on it, so real customers get rejected at your signup form and you never find out. SignupScore reviews every domain before it blocks anything. It also catches dynamic DNS, gibberish addresses, typo domains like gmial.com, role accounts, and the same person returning with a different spelling. Free plan is 250 checks a month. API and dashboard.