Regex Cheat Sheet

.

Any character except newline

\d

Digit [0-9]

\D

Non-digit

\w

Word char [A-Za-z0-9_]

\W

Non-word char

\s

Whitespace (space, tab, newline)

\S

Non-whitespace

\b

Word boundary

\B

Non-word boundary

\n \r \t

Newline, carriage return, tab

\\ \. \+

Escape special characters

[abc]

Any of a, b, c

[^abc]

Not a, b, or c

[a-z]

Range a to z

[A-Z0-9]

Uppercase letters or digits

[a-zA-Z]

Any letter

a?

0 or 1 of a (optional)

a*

0 or more of a

a+

1 or more of a

a{3}

Exactly 3 of a

a{2,}

2 or more of a

a{2,5}

Between 2 and 5 of a

a*?

Lazy (minimal) match

.*?

Minimal any-char match

^

Start of string (or line in /m)

$

End of string (or line in /m)

^word$

Exact match for "word"

\A \Z

Start/end of string (not line)

(abc)

Capturing group

(?:abc)

Non-capturing group

(?<name>abc)

Named capture group

\1 \2

Backreference to group 1, 2

\k<name>

Backreference to named group

a|b

a or b (alternation)

(?=abc)

Positive lookahead

(?!abc)

Negative lookahead

(?<=abc)

Positive lookbehind

(?<!abc)

Negative lookbehind

\d(?=px)

Digit followed by 'px' (px not included)

/pattern/i

Case-insensitive

/pattern/g

Global (all matches)

/pattern/m

Multiline (^ $ match lines)

/pattern/s

Dot matches newline

/pattern/u

Unicode mode

^\d+$

Only digits

^[a-zA-Z0-9]+$

Alphanumeric only

^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$

Email address

^https?:\/\/[^\s]+$

URL (http or https)

^\+?[1-9]\d{1,14}$

E.164 phone number

^\d{4}-\d{2}-\d{2}$

ISO date YYYY-MM-DD

^([01]\d|2[0-3]):[0-5]\d$

Time HH:MM (24h)

^#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3})$

Hex color

\b\d{1,3}(\.\d{1,3}){3}\b

IPv4 address

^[a-z0-9]+(-[a-z0-9]+)*$

URL slug (kebab-case)

(?=.*[A-Z])(?=.*\d).{8,}

Password: 8+ chars, 1 upper, 1 digit