Valid email characters
According to the Internet Engineering Task Force (IETF) and the Multipurpose Internet Mail Extensions (MIME) standard, a valid email address consists of the following characters:
Local Part:
- Alphanumeric characters (letters and numbers): a-z, A-Z, 0-9
- Special characters:! # $ % & ' * + - / =? ^ _ ` { | } ~
- Dot (.) is allowed, but not as the first or last character
Domain:
- Alphanumeric characters (letters and numbers): a-z, A-Z, 0-9
- Hyphen (-) is allowed
- Dot (.) is allowed, but not as the first or last character
Top-Level Domain (TLD):
- Alphanumeric characters (letters and numbers): a-z, A-Z, 0-9
- Hyphen (-) is allowed
- Dot (.) is allowed, but not as the first or last character
Examples of valid email addresses:
Invalid email characters:
- Space ( ) characters
- Tab (\t) characters
- Newline (\n) characters
- Carriage return (\r) characters
- Backslash () characters
- Quotation marks ("") characters
- Angle brackets (<>) characters
- Ampersand (&) characters (unless escaped with a backslash)
Special considerations:
- Internationalized Domain Names (IDNs) may contain non-ASCII characters, such as accented letters or non-Latin scripts.
- Email addresses can contain internationalized characters, such as non-ASCII characters, but these may not be universally supported.
- Some email providers may have additional restrictions on valid characters, so it's always a good idea to check with the provider before sending an email.
Keep in mind that while these are the general guidelines for valid email characters, some email providers or systems may have stricter or more relaxed rules.