Email aliases explained
Alias, plus tag, and catch-all all forward mail to one inbox but work differently. Here is how each one actually behaves and where each falls short.
What is an email alias?
An alias is a second address that forwards to a real mailbox. It is a separate name, not a modified version of your main address, so it does not reveal the address behind it just by looking at it. Give a different alias to every service and each one can be turned off individually without touching the others.
What is plus subaddressing (the +tag trick)?
Plus subaddressing takes your existing address and appends a tag after a plus sign, like [email protected]. Most major providers deliver that straight to [email protected] and ignore everything after the plus. It is useful for sorting mail with filters, since the tag tells you where the address was given out.
It is not privacy protection. The tag sits in plain text in the address, so anyone who receives it can see your real address just by deleting everything from the plus sign onward. A site that wants to bypass your organization can strip the tag and reach you at your unmodified address anyway, which defeats the entire point if the goal was to hide the real address.
What is a catch-all address?
A catch-all accepts mail sent to any name at a domain you control, not just the ones you specifically created. Send mail to literally [email protected] and it arrives, no setup needed per address. That flexibility is also the weakness: it accepts mail to typos and to addresses you never made on purpose, so a catch-all domain tends to collect more spam over time than one with individually created mailboxes.
How do the three actually compare?
| Alias | Plus tag (+alias) | Catch-all | |
|---|---|---|---|
| Hides your real address | Yes | No, trivially stripped | Depends on domain setup |
| Can disable one without affecting others | Yes, per alias | No, same underlying inbox | Yes, per address if managed individually |
| Setup effort | Create each one | None, just add the tag | One domain-level setting |
| Accepts typos and unintended addresses | No | No | Yes, by design |
Why does a stripped +tag not stop a determined data broker?
A data broker or a company reselling a mailing list only needs to remove the plus and the tag to recover your unmodified address. That is a one-line string operation, not a security bypass. The tag was never designed to resist that; it was designed to help you sort your own inbox, and it does that job well. Treat it as an organizing tool, not a privacy wall.
A regmail.me address is closer to a true alias than a plus tag. It is a separate name on a real domain, so a service that has it cannot derive a different address behind it the way a plus tag exposes the underlying inbox.
Which one should you actually use?
- Use plus tags for quick, low-stakes sorting inside an inbox you already have
- Use a real alias or a separate address when you want to fully cut a leak off, not just label it
- Avoid relying on a catch-all as your main privacy layer, since it also collects everything sent to a typo or a guessed name
- For anything sensitive, a receive-only address dedicated to that one purpose is the strongest of the three
Frequently asked questions
Is a plus tag (+alias) the same as a real email alias?
No. A real alias is a separate address that hides the mailbox behind it. A plus tag is your same address with a suffix that anyone can strip in one step to recover the original.
Can a company see through a +tag to your real address?
Yes, easily. Removing everything after the plus sign reveals the exact address underneath, so a plus tag never actually hides which mailbox receives the mail.
What is the main risk of a catch-all address?
It accepts mail sent to any name at the domain, including typos and guessed addresses nobody was given on purpose, so it tends to accumulate more spam than a domain with individually created mailboxes.
Which option actually stops one leak from reaching other accounts?
A real alias or a dedicated separate address does, because disabling it does not touch anything else. A plus tag does not, since it is the same underlying mailbox with a label that is trivial to remove.
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