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Gmail allows you to create unlimited unique addresses by using the + symbol. so you could do: username+trello@gmail.com. It's worked well for me for a few years.

The only downsides I see are that (very few) sites still complain about the perfectly legal + symbol and some sites / bots are probably starting to reverse engineer that since it still exposes your username. But so far, I've yet to have a single site or service expose my primary mail account, so it at least helps.

Finally: this is a fantastic hack for testing your own signup flows. :)

2 comments

Hi toddmorey, yes a well-known trick ;) The downside is that the + part can be easily removed by spammers.

I have a personal Gmail account that I give to real life friends and real met-in-person humans who want to directly contact me. And then a web gmail where everything is labeled with a plus(if websites don't accept the plus, I use a series of periods in the first portion of the email to make it unique. Then, I forward all emails with whitelisted +whatever's from my web mail to my personal mail.

Not a Gmail specific thing. That's something you can do with email in general.

Not really, according to the spec the '+' can be interpreted as part of the email address. The approach gmail takes seems to have gained widespread adoption, but it's not mandated by the spec.

Believe I saw this on HN recently: http://haacked.com/archive/2007/08/21/i-knew-how-to-validate...

I believe it is Gmail specific. Cursory search reveals that sendmail does that too, but I don't think it is specified in RFC. Feel free to correct me if I'm wrong.

It's more Sendmail and Exim and others did it, and Gmail does it too - not the other way around;)

With qmail the "standard"[1] was username-alias@example.com, rather than username+alias@example.com. I rather prefer that - but then my (user)name(s) don't contain any hyphens.

Either way I think it looks better with system usernames - firstname.lastname@example.com was/is usually handled as a separate form of alias look-up anyway.

[1] http://www.lifewithqmail.org/lwq.html#dot-qmail-files See section "4.1.5. extension addresses"

[ed: and I recall using tmda as an anti-spam system - it inserts an encrypted tag in the alias portion, that can be stamped with an expiry date, and tied to a sender address (eg hmac(userkey, sender@example.com+01012018) => xyxyzzzzz - give sender@example.com the address user-xyxyzzzz@example.net - and mail to that address will be accepted from only sender@example.com until 1/1/2018.

http://tmda.sourceforge.net/cgi-bin/moin.cgi/AboutTmda ]

I don't have a source to a RFC, but all email's I've ever used let me do this. Including multiple different hosting services with my own domains, and my current work which is MS Exchange.