Are single quotes legal in the name part of an email address?

Question

For example:

jon.o\'conner@example.com ?

Answer 1

The format for email addresses is defined in RFC 5322; The local part (i.e. recipient) may use any of these ASCII characters:

• Uppercase and lowercase English letters (a–z, A–Z)
• Digits 0 to 9
• Characters ! # $ % & ' * + - / = ? ^ _ ` { | } ~
• Character . (dot, period, full stop) provided that it is not the first or last character, and provided also that it does not appear two or more times consecutively (e.g. John..Doe@example.com).

From this, you can see that single quotes are valid for the recipient address