What characters are allowed in an email address?

See RFC 5322: Internet Message Format and, to a lesser extent, RFC 5321: Simple Mail Transfer Protocol. RFC 822 also covers email addresses, but it deals mostly with its structure: addr-spec = local-part “@” domain ; global address local-part = word *(“.” word) ; uninterpreted ; case-preserved domain = sub-domain *(“.” sub-domain) sub-domain = domain-ref … Read more