Can you explain how the backend works? Will it block Apple's 'hide my email' feature from functioning with valid @icloud.com addresses, or similar 'valid' domains with potentially disposable email addresses?
My team maintains a list of disposable domains actively, if the target domain couldn’t match existing records, we will verify its DNS record (coming soon) :PPP
Developers and regex on email is always a terrible idea. So many fail to understand what the RFC allows (virtually anything). Can't tell you how often websites will reject an email address with a two-character localpart :-(