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Is an apostrophe (') in an email address really valid?

Posted on 2016-10-20
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Last Modified: 2016-10-20
I've had over 150,000 people sign up through my server and only today I've encountered my first email address with an apostrophe.

I always thought that o'connor@example.com was invalid. And many of the filters and tests that you run come back showing that is invalid.

But in doing some research about the "technically" allowed characters all indications show that to be a valid.  (see wikipedia article).

So is this one of those things that is "on the books" that it is technically okay but in reality no one does it. Gmail doesn't allow it, an online test tool like this doesn't allow it (http://verify-email.org/) and most PHP and JavaScript email validators don't allow it although it looks like angular does (http://www.w3schools.com/angular/tryit.asp?filename=try_ng_validate_required)

So my question is, what's the practical reality. Although permissible, does anybody really do it?  I had my first one in over 150,000 entries. Is that how rare it is?

Thanks for any insight you can give.
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Question by:pkonstan1
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Dr. Klahn earned 500 total points
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As you've discovered, technically ... it is valid.  In practice, so many email validation filters reject it that is is not practical to use.  I have never seen such an address arrive at one of my systems in the last 20 years.
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by:pkonstan1
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Since I have my own server and ability to create email address, I created the above email address on my server. I then created a facebook page with that email address, which they allowed me to do, and the verification code came right through. So the big giant of Facebook does allow it and it works.

But I'm like you in that in my 40 years of working with computers, I've never seen it. That's why it kind of freaked me out today. There are some database queries that I run that I just don't account for there to be an apostrophe in the email address.

Even the PHP filter validation for email doesn't allow it. http://www.w3schools.com/php/showphp.asp?filename=demo_form_validation_special

Thanks for confirmation of my findings.
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by:pkonstan1
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Thanks for the confirmation.
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