RFC Standard says the max email size is 320 (actually 256 according to http://www.dominicsayers.com/isemail/). Is there any conceivable scenario where email addresses could end up being bigger than this?
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Flag this as subjective. – Andrew Sledge Jun 24 '09 at 18:01
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3Its an existential question (does their exist). That's an objective question. Either the situation exists or it doesn't. I'm not quite sure why you would think it would be subjective. – Daniel Jun 24 '09 at 18:03
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345 -- https://laughingsquid.com/the-worlds-longest-active-email-address/ – John Henckel Jun 20 '17 at 22:53
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411 is the new record-- (https://recordsetter.com/world-record/email-address/4310) – Daniel Carrera Jul 05 '20 at 06:15
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Read this: http://www.eph.co.uk/resources/email-address-length-faq/ The upshot of it is that you should use 254 characters to store email addresses, because that is the maximum allowed in an SMTP transaction. This is specified in RFC5321 (your article says so, and is actually quoted in mine), which is authoritative.
psanf
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Wayback archive link: https://web.archive.org/web/20160404205612/www.eph.co.uk/resources/email-address-length-faq/ – Jeremy W. Sherman Jul 27 '21 at 19:03
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To be honest, even if someone had a valid email address beyond 256/320 chars it would be a major pain to use.
Anyone using an email address that is even half as big as that (128 chars) needs to trim back!
although on the plus side, they likely get no spam!
For example both of these would be unusable:
//long domain
joe.shmoe@someveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryverylogdomain.com
//long username
someveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryverylonguser@aregularlengthdomain.com
scunliffe
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About 4 years I've seen one free email service claiming to have a really long domain name (there were about 200 characters in it). And this is perfectly legimate. I don't think it is good to invent our own "no more than 128 characters" policies if we want to be interoperable. Even if it is very unlikely to occour that one has such a long address. – drdaeman Jun 24 '09 at 18:37
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although it is valid... I just don't see it as realistic. I'm not saying to restrict the size to 128, just that the reality of a usable email address at 128+ characters is questionable in its own right. e.g. the longest one I have in my address book is 42 characters (of 2,000+/- entries). By all means keep the DB column size at 254, 256, 320 or whatever... but I wouldn't *increase* this value because someone decided to *try* and create a 352 character email address. – scunliffe Jun 24 '09 at 20:11
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This guy managed to have a 345 character-long email address and make it work:
The World’s Longest Active Email Address
Admittedly, such a long email address is completely pointless.
Luis Alonso Ramos
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