RE: "International" email addresses [I18N-ACTION-374]

Dear Steven and XForms,

Firstly, the WG *very much* welcomes further discussion from any and all on this list: this is how we find stuff out. (Thanks to Anne, JcK, Jungshik, and Shawn for contributions so far)

This is just a note to let you know that the Internationalization WG has taken up a discussion of this topic, which has, obviously, some interesting issues associated with it. We’re aware that, although “EAI” (email address internationalization) has been slow to mature and gain traction, there are serious efforts from vendors and in various countries to bring non-ASCII mail addresses into the mainstream.

This doesn’t play well with the current description in HTML (cited by Anne) or various other places. As Shawn and John note, a regex description of IDNA is probably impossible. At best, such a regex would be an approximation.

The Internationalization WG is creating a discussion page to capture the issues [1]. We have not had a chance to discuss the issue in greater depth yet, but the WG’s consensus is that this is an interesting problem needing further investigation and documentation. Please note that, owing to the Thanksgiving holiday in the USA, the Internationalization WG is unlikely to make much more of a response for a couple of weeks.

Regards (for I18N),



From: Shawn Steele []
Sent: Wednesday, November 19, 2014 11:37 AM
To: Jungshik SHIN (신정식)
Cc: Anne van Kesteren; Steven Pemberton;; Forms WG
Subject: RE: "International" email addresses

Validating the IDN part is much more complicated than validating the local part, because you need to know the IDN rules.  Which means it probably isn’t just a “simple” regex.

So maybe the rule should allow Unicode in the domain part and encourage complete IDN validation as an additional step?


From:<> [] On Behalf Of Jungshik SHIN (???)
Sent: Wednesday, November 19, 2014 10:53 AM
To: Shawn Steele
Cc: Anne van Kesteren; Steven Pemberton;<>; Forms WG
Subject: Re: "International" email addresses deals with it (EAI support in email form validation) although the summary is a bit misleading (it only talks about IDN).


On Wed, Nov 19, 2014 at 10:07 AM, Shawn Steele <<>> wrote:
Updating that to support EAI would be good.

-----Original Message-----
From:<> [<>] On Behalf Of Anne van Kesteren
Sent: Wednesday, November 19, 2014 2:07 AM
To: Steven Pemberton
Cc:<>; Forms WG
Subject: Re: "International" email addresses

On Wed, Nov 19, 2014 at 11:00 AM, Steven Pemberton <<>> wrote:
> So as far as I can see, an internationalised email address is:
>  address: atom-list "@" atom-list.
>  atom-list: atom ( "." atom )*
>  atom: C+
>  C: any character in the world EXCEPT (),.:;<>@[\]
> a) Do you agree?
> b) It was really hard to find this out. The internet is rife with
> people asking and getting bad answers. Please help the internet by
> being definitive.

I recommend matching HTML's definition:


Received on Thursday, 20 November 2014 16:38:17 UTC