Disposable Inbox vs Email Alias: When to Use Which
“Don’t give sites your real email” has two common answers, and they are not the same tool. An alias (SimpleLogin, Addy.io, Firefox Relay, Apple’s Hide My Email) hands out a stand-in address that forwards to the inbox you already have. A disposable inbox like ztrash is a separate inbox that receives mail directly and then disappears. The difference decides which threats each one actually addresses.
How an alias works
You keep one real mailbox and generate a new address per site. Mail to the alias is forwarded on. If a site leaks or sells the address, you disable that one alias and the spam stops, without changing anything else. Most alias services also let you reply through the alias, so the other side never learns your real address.
That is genuinely useful, and for an account you intend to keep it is the better tool. But note what it does not do: your real mailbox still exists, still holds all the mail, and the alias provider knows both halves of every mapping.
How a disposable inbox works
There is no forwarding and no mailbox behind it. Mail arrives at an inbox that exists on its own, you read it, and the inbox is purged on expiry or the moment you destroy it. Nothing points anywhere, because there is nowhere for it to point.
What each one hides, and from whom
- From the site you signed up with: both work. It sees a stand-in address either way.
- From data brokers correlating breaches: both work, as long as you use a fresh address per site.
- From the provider in the middle: only the disposable inbox. An alias service holds a table mapping every alias to your real address, and it is that table’s existence, not anyone’s good intentions, that determines what can be leaked or compelled.
- From whoever reads the mail on disk: only if the mail is sealed. Alias providers forward plaintext by default, though some support forwarding to your PGP key. A ztrash inbox seals each message to a key only your browser holds.
The account problem
To use an alias service you need an account with it, a real mailbox to forward to, and, above the free tier’s cap, a payment method with your name on it. Those three facts are the identity the aliases were supposed to protect, now concentrated in one provider. Apple’s Hide My Email is the sharpest version of this: it is excellent at hiding your address from a merchant and useless at hiding you, because it is welded to an Apple Account with your name and card on it. (The free variant only works through Sign in with Apple; standalone use needs paid iCloud+.)
A disposable inbox has no account by construction. You pay with shielded Zcash, which settles the bill without a name, a card, or a phone number, and the inbox opens at a private URL. There is no login to phish and no mapping table to subpoena.
Use an alias when
- You want the account long-term and will need password resets.
- You need to reply, not just receive.
- You’re mainly defending against spam and breach correlation, and you trust the provider with the mapping.
- The service is one you’d be comfortable naming to anyone.
Use a disposable inbox when
- You need one verification code or one gated download and nothing after that.
- You don’t want the signup linked to your identity at all, not just to your address.
- You don’t want to hold an account anywhere to make it work.
- You’d rather the mail be unreadable on the server than forwarded in plaintext.
They compose
This isn’t an either/or. Aliases are the right default for the twenty accounts you actually keep; a disposable inbox is the right tool for the hundred one-shot forms that stand between you and a download. Using both means your real address stays out of both piles.
One honest limit on our side: ztrash inboxes are receive-only and expire, on purpose. If you need to reply next month, you want an alias. If you need to never be found, you want this.