Definition
Disposable email address: A temporary inbox from a service such as Mailinator or Guerrilla Mail, used to receive one signup email and then abandoned or deleted automatically. The address may pass an SMTP check, but nobody will read later mail sent to it.
How disposable email services work
Some services give anyone a public inbox on a shared domain: type a name, read whatever arrives, no password. Others hand out a random address that deletes itself after a set time.
New domains appear constantly, because operators rotate them as sites start blocking the old ones. Any block list has to keep up.
Disposable addresses vs forwarding aliases
Privacy relays such as Apple Hide My Email and Firefox Relay are not disposable. They forward to a real, long-lived inbox, and the person reads your mail.
Blocking them punishes privacy-minded customers who are often highly engaged. Block throwaway inboxes, allow relays.
How to block disposable emails at signup
Check the domain against a maintained disposable list as the form is submitted, and show a clear message asking for a permanent address.
Do it in real time, on the form, rather than in a nightly cleanup. By then the free trial has been used, the coupon redeemed and the welcome series sent to an inbox that no longer exists.
How RocketVerifier handles it
We flag disposable domains using two public community blocklists plus our own allow and deny overrides, refreshed continuously, and return them as undeliverable with sub_status disposable. RocketShield adds the same check to any signup form with one script tag. Our free disposable email checker tests an address or domain without using credits.