Email address internationalization
The standards (RFC 6530 to 6533) that allow email addresses and headers in any script, such as Chinese, Arabic or accented Latin, encoded in UTF-8.
What it means
Before EAI the local part of an address had to be ASCII, and non-Latin domains could appear only in their punycode form. RFC 6530 gives the framework, RFC 6531 the SMTPUTF8 extension that lets servers exchange such addresses, RFC 6532 UTF-8 header fields, and RFC 6533 delivery status notifications that can report on them.
Support is the hard part. Every server on the path, and the recipient's mail program, must handle UTF-8 addresses; when one does not, the message bounces, with enhanced codes such as 5.6.7, because a non-ASCII local part has no ASCII fallback. Sign-up forms should accept such addresses and store them as UTF-8.
Related terms
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Sources
What this definition rests on. The wording is ours; the facts are theirs.
All 432 terms in the glossaryThe wiki: blocklists and bounce codes