EmailAddress GraphQL Scalar Specification

EmailAddress — GraphQL Custom Scalar

Author - Juke-Duke

Date - 2023-02-06

This is a String-based Scalar.

License and Copyright

Copyright © GraphQL contributors. This specification is licensed under OWFa 1.0.

Overview

This Scalar represents a valid electronic mail address using a simplified version of RFC 5322.

The format of an email address is local@domain, where the local part may consist of up to 64 UTF-8 characters, the domain part may consist of up to 255 UTF-8 characters, and the two parts are separated by an @ sign.

Other formats, including using square-bracketed IP addresses in the domain part, and quoted-string local parts, are not supported for simplicity.

The local part may contain any of the following ASCII characters:

• Uppercase and lowercase Latin letters A to Z and a to z
• Digits 0 to 9
• Printable characters !#$%&'*+-/=?^_`{|}~
• Dot ., provided that it is not the first or last character and provided also that it does not appear consecutively

The domain part may contain any of the following ASCII characters:

• Uppercase and lowercase Latin letters A to Z and a to z
• Digits 0 to 9, provided that top-level domain names are non-all-numeric (.com, .net, .org, .b2b, etc.)
• Hyphen -, provided that it is not the first or last character

Examples

The general format is described in RFC5322 Section 3.4.1. These examples are taken from WikiPedia, which is also based off of RFC5322 Section 3.4.1.

These are valid examples:

String	Explanation
simple@example.com	An EmailAddress without any special characters.
very.common@example.com	An EmailAddress with a dot inside the local part.
disposable.style.email.with+symbol@example.com	An EmailAddress with dots and a plus sign inside the local part.
other.email-with-hyphen@example.com	An EmailAddress with a dot and hyphens inside the local part.
fully-qualified-domain@example.com	An EmailAddress with hyphens inside the local part.
user.name+tag+sorting@example.com	An EmailAddress with a dot and plus signs inside the local part
x@example.com	An EmailAddress with a single character in the local part.
example-indeed@strange-example.com	An EmailAddress with a hyphen in both the local and domain parts.
test/test@test.com	An EmailAddress with a slash in the local part.
admin@mailserver1	An EmailAddress with no top-level domain. This is highly discouraged.
example@s.example	An EmailAddress with a dot in the domain part.
mailhost!username@example.org	An EmailAddress with a bang in the local part.
user%example.com@example.org	An EmailAddress with a percent sign in the local part.
user-@example.org	An EmailAddress with a hyphen in the local part.
non-all-numerical-top-level@domain.g2g	An EmailAddress with a non-all-numerical top-level domain.

These are invalid examples:

String	Explanation
Abc.example.com	No @ sign separating the local and domain components.
A@b@c@example.com	Only one is allowed to divide the local and domain components.
a"b(c)d,e:f;g<h>i[j\k]l@example.com	The local part contains invalid characters.
just"not"right@example.com	Quotes are not allowed in the local component.
this is"not\allowed@example.com	Spaces and backslashes are not allowed in the local component.
this\ still\"not\\allowed@example.com	Spaces and backslashes are not allowed in the local component.
1234567890123456789012345678901234567890123456789012345678901234+x@example.com	The local component is longer than 64 characters.
i_like_underscore@but_its_not_allowed_in_this_part.example.com	Underscores are not allowed in the domain component.
QA[icon]CHOCOLATE[icon]@test.com	Non UTF-8 characters are not allowed in the local component.
all-numerical-top-level@domain.3778	Top-level domains cannot be all numerical.

This regex provided below follows the above examples:

^(?!\.)(?!.*\.\.)[a-zA-Z0-9!#$%&'*+-/=?^_`{|}~\.]{0,63}[^\.]@(?!\-)[a-zA-Z0-9-]+[^\-]\.?(?!\d+$)[a-zA-Z0-9]{2,255}$

Name

The recommended name is EmailAddress. Alternatives may be Email, E-Mail, MailAddress.

Result

Every result must follow the valid String formats as described above.

Input

Every input following the valid String formats as described above must be accepted.

References

RFC 5322

RFC 6531

Wikipedia