regex101: JavaScript Match Workspace

Pro

^start of line

Group 1([a-z\d\.-]+)

Character Class[a-z\d\.-]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

\da digit

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

@the literal @ (64₁₀ / 100₈ / 40₁₆)

Group 2([a-z\d-]+)

Character Class[a-z\d-]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

\da digit

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 3([a-z]{2,8})

Character Class[a-z]{2,8}

{2,8}matches between 2 and 8 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

Group 4(\.[a-z]{2,8})?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[a-z]{2,8}

{2,8}matches between 2 and 8 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

$end of line

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

g modifier: global. Finds all matches instead of stopping after the first

26 tokens

Regular Expression

^([a-z\d\.-]+)@([a-z\d-]+)\.([a-z]{2,8})(\.[a-z]{2,8})?$

New

VALID EXAMPLES: 
dominicjames@coelho.com
fake-but-valid@dominic.digital
legit.but.long.email123.qwerty@gmx-email.com

NOT VALID EXAMPLES: 
not!valid@google.com
$$@gmail.com
dom_coelho@gmail.com

LIMITATIONS (false positive): 
1@2.zz

LIMITATIONS (false negative):
underscores_not_accepted@live.com

Substitution

VALID EXAMPLES: 
dominicjames@coelho.com
fake-but-valid@dominic.digital
legit.but.long.email123.qwerty@gmx-email.com

NOT VALID EXAMPLES: 
not!valid@google.com
$$@gmail.com
dom_coelho@gmail.com

LIMITATIONS (false positive): 
1@2.zz

LIMITATIONS (false negative):
underscores_not_accepted@live.com