Why not just use the plus sign

Gmail, Outlook, Fastmail and most others let you put a tag after a plus: you+shop@gmail.com lands in you@gmail.com. It is free, it needs no account anywhere, and it works right now.

For a lot of people it is genuinely enough. Here is where it stops being enough.

Your real address is right there in the string

you+shop@gmail.com contains you@gmail.com. Deleting the four characters either side of the plus is not an attack, it is a text operation, and anyone with a list of these addresses does it in one pass.

Every marketing platform knows about plus addressing. Every list broker knows. It is not obscure.

You cannot turn one off

This is the real problem, and it is structural.

Once you+shop@gmail.com is leaking, your options are a filter rule that deletes the mail after it arrives, or changing your actual email address. There is no third option, because the tag was never a separate address, just a label on the only address you have.

An alias is a distinct address. Deleting it means mail to it is refused before it reaches you at all.

Plenty of sites reject it

Signup forms that validate email addresses with a homemade regular expression frequently reject the plus, and some sites reject it deliberately, because they know what you are doing.

Aliases look like ordinary addresses because they are ordinary addresses.

You cannot reply from it

Reply to something sent to you+shop@gmail.com and it goes out from you@gmail.com. Whatever you were trying to keep separate is now joined up.

Aliases reply as themselves.

Every tag points at the same place

Plus addressing tells you who leaked your address. It does not stop them, and it does not stop the next person who buys the list from reaching you at the address they now hold.

When plus addressing is the right answer

If you want to know which shop sold your address and you do not mind them having it, it is free and it works. It is a labelling system.

An alias is a barrier. Different tool.

Last checked: August 2026.

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