What is a disposable email address?
An address you use once and abandon. It receives mail like any other, belongs to no account, and is not connected to anything else you own — so throwing it away costs you nothing, because there is nothing to keep.
How it works
A domain’s MX records say which servers accept its mail. A disposable-address service points those at itself with a catch-all rule, so mail to any address on that domain is accepted rather than only to addresses somebody set up in advance. That is what makes it possible to hand out a fresh address the instant you ask for one: nothing has to be created first, because the domain already accepts everything.
The address you get is random rather than chosen. On this service it is ten characters drawn from a cryptographic source — a little under fifty bits, which is enough that guessing someone else’s is not a realistic thing to attempt. That secrecy is doing real work: the address is the only credential involved, and anyone who has it can read the mailbox.
What it protects you from, and what it does not
It stops one specific thing well: your real address ending up somewhere you did not intend.
- Marketing lists. Whatever the site sends goes to an address you have stopped reading.
- Breach correlation. An address is the join column between leaks. A different one per site means there is nothing to join.
- Being sold on. Lists get traded. This one arrives attached to nothing.
It does nothing about the rest. The site still sees your IP address and your browser, and still has whatever else you typed into the form. It is one tool for one problem, and pretending otherwise is how people end up trusting it with things they should not.
What is stored, and for how long
Here, messages are kept for seven days and then deleted. The mailbox lives thirty days from the last time it was opened, so an address you keep using keeps working and one you used once goes away.
Mailboxes outlive their messages deliberately. Deleting the mailbox row would release the address to be handed to somebody else, and any sender still holding it would then be delivering to a stranger. Attachments are named but never stored — the file itself is discarded when the message arrives.
Why some sites block them
Signup forms keep lists of known disposable domains and reject addresses on them. From the site’s side the reasoning is ordinary: single-use signups skew their numbers, and abuse arrives through throwaway addresses more often than through real ones.
There is no way around this that is worth doing, and no service that is permanently unblocked — a domain that becomes popular enough to be useful becomes popular enough to be listed. When a form refuses the address, use your real one or skip the site.
When to use a different tool
For an account you intend to keep, use an alias service or your real address. A throwaway address has no password, no recovery, and a deliberate expiry date; anything whose password reset would need to reach you should not be behind one. More on choosing what to give a signup form.