Use an alias when you want the sender to be able to reach you for years without learning your real address, and a disposable inbox when you want one message now and nothing after that. An alias is a forwarding label: mail sent to it arrives in your ordinary mailbox, where it stays, gets searched and gets backed up like everything else. A disposable inbox is a different mailbox entirely, hosted by someone else, which holds the message for a while and then stops existing. That single structural difference decides every practical question about them — replies, lifespan, recovery, and which sites will accept them.
The real difference is where the mail lands
Both tools stop a company from seeing yourname@gmail.com. What happens next is not the same at all.
With an alias, the mail is yours. It travels through the alias provider and lands in your inbox, so you can reply (the provider rewrites the reply so it appears to come from the alias), search it in three years, and notice if something arrives from a sender you had forgotten about. The cost is that the relationship is permanent until you cancel it, and that someone now holds a mapping between the alias and your real address.
With a disposable inbox, the mail is not yours and never was. It sits on the provider's server, you read it in a browser, and when the address expires the mailbox and its contents go with it. Nothing is forwarded, nothing is stored on your side, and there is no mapping to your real address because you never supplied one. The cost is that you have no way back: no replies that arrive anywhere you will see later, no password reset in six months, no proof of purchase.
The four options, concretely
Plus-addressing (free, already in your account)
Gmail, Outlook, Proton, Fastmail and most other providers deliver mail sent to yourname+shop@example.com straight to yourname@example.com. Nothing to set up: invent the tag at the moment you type it, then filter on it later. It is genuinely useful for sorting mail and for finding out who leaked an address, because the tag you used travels with the leak.
It is not a privacy measure. Your real address is sitting in plain sight on the left of the plus sign, and stripping the tag is one line of code that bulk-mail tools have been doing for years. A fair number of signup forms also reject the + character outright. Treat plus-addressing as labelling, not hiding.
Apple Hide My Email
When you use Sign in with Apple, you are offered a random @icloud.com address that forwards to whatever address is on your Apple account. With a paid iCloud+ subscription you can also generate these addresses on demand for forms that have no Apple button at all. Replies work, each address can be labelled and switched off individually, and the whole thing is managed in system settings.
The limits are the obvious ones: it ties your aliases to an Apple account you presumably intend to keep, and it is comfortable only inside Apple's ecosystem. If you later leave, the addresses leave with you.
Dedicated alias services
SimpleLogin, Addy.io and Firefox Relay all do one job: generate an address, forward it, let you reply through it, let you disable it. The paid tiers add unlimited aliases and — the feature that actually matters — aliases on a domain you own, which means nobody can tell your addresses are aliases and you can move providers without losing them. Several of these projects are open source and can be self-hosted if you want the mapping on your own machine.
This is the right tool for accounts you intend to keep: a bank, an airline, a utility, a shop you reorder from. You get a distinct address per company, which contains any future leak to that one company, and you still get the mail forever.
Disposable inboxes
A disposable inbox gives you an address and a readable mailbox with no account, no password and no forwarding. You open a page, the address already exists, and mail sent to it appears in front of you within seconds. It is the only one of the four that holds the message somewhere other than your own mailbox, and the only one that disappears on its own.
That makes it right for a specific and very common situation: a site demands an email address, you want the one thing behind the confirmation link, and you have no intention of hearing from them again. A download, a PDF gated behind a form, a forum you will post in twice, a one-off discount code, a wifi portal. Our comparison of temp mail, VPNs and aliases goes further into what each of those actually conceals, which is less overlapping than it first appears.
Which one for which job
- Anything with money or recovery attached — bank, payroll, tax, insurance, your domain registrar: your real address, or an alias on your own domain. Never a disposable inbox.
- Shops, airlines, subscriptions you expect to use again: an alias. You want the receipts and the delay notices, just not the marketing list that follows.
- A single confirmation link you need in the next two minutes: a disposable inbox. An alias here is work you have to undo later.
- Free trials and promo codes: depends on whether you might want the account. If the trial could become a paid subscription, use an alias.
- Testing your own software: disposable inboxes, by the dozen. No cleanup, no quota, no polluting a real mailbox with test mail.
- A form you suspect exists only to collect addresses: disposable inbox, and do not give the form anything else either.
Where each one breaks
Aliases break on the mapping. Someone — Apple, SimpleLogin, Mozilla, or you if you self-host — holds a record linking the alias to your real address, and that record is a target. They also break quietly: an alias forwards for years, so a list sold in 2029 still reaches you unless you remember to turn the alias off, and most people never do.
Disposable inboxes break on permanence and on secrecy. Once the address expires, the mail is gone and no support ticket will bring it back — we wrote about why a temp mail cannot be recovered because people ask after the fact, when it is too late. On most services the address is also reachable by anyone who types it, so a confirmation code sitting in one is not private for as long as it exists. That is a reason to use them for throwaway signups and not for anything you would mind a stranger reading; the trade-offs are laid out in what a disposable address can and cannot protect.
Both break on rejection. Plenty of sites maintain blocklists of disposable domains, and a growing number also block the better-known alias providers. An alias on your own domain is the only version of this that is effectively unblockable, which is one more argument for paying for a custom domain if you are going to rely on aliases at all.
Most people should use both
The two tools are not competing for the same signups. Sort by one question: will I ever need mail from this sender again? If yes, an alias, because you want delivery to keep working and you want to be able to reply. If no, a disposable inbox, because the best way to not be on a list in two years is to have handed over an address that stopped existing.
A reasonable setup is three layers: your real address for the handful of accounts that are effectively identity documents, aliases on a domain you own for the few dozen companies you deal with repeatedly, and a disposable inbox for everything else. The third layer is the one that absorbs most of the volume, and it is the one that needs no maintenance at all.