Regular Expressions 101

^start of string

Group 1([A-Z0-9._%-]+@[A-Z0-9-]+\.[A-Z]{2,4}(\.[A-Z]{2,4})?)

Character Class[A-Z0-9._%-]+

+matches at least one character from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case insensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

%the literal % (37₁₀ / 45₈ / 25₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

@the literal @ (64₁₀ / 100₈ / 40₁₆)

Character Class[A-Z0-9-]+

+matches at least one character from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case insensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[A-Z]{2,4}

{2,4}matches between 2 and 4 characters from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case insensitive)

Group 2(\.[A-Z]{2,4})?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[A-Z]{2,4}

{2,4}matches between 2 and 4 characters from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case insensitive)

$end of string, or before its final line terminator

Global pattern flags

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^([A-Z0-9._%-]+@[A-Z0-9-]+\.[A-Z]{2,4}(\.[A-Z]{2,4})?)$

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