Validation

Match a CSS hex color

Flags: gi

Match CSS hex colors: #RGB, #RRGGBB, or #RRGGBBAA.

Pattern

Regular expression

#(?:[0-9a-f]{8}|[0-9a-f]{6}|[0-9a-f]{3})\b

Order matters: try 8-digit (RGBA) then 6-digit (RGB) then 3-digit shorthand. The word boundary prevents partial matches inside longer hex strings.

JavaScript

const re = /#(?:[0-9a-f]{8}|[0-9a-f]{6}|[0-9a-f]{3})\b/gi;

Python

re.findall(r"#(?:[0-9a-f]{8}|[0-9a-f]{6}|[0-9a-f]{3})\b", text, re.I)

re := regexp.MustCompile(`(?i)#(?:[0-9a-f]{8}|[0-9a-f]{6}|[0-9a-f]{3})\b`)

Java

Pattern.compile("#(?:[0-9a-f]{8}|[0-9a-f]{6}|[0-9a-f]{3})\\b", Pattern.CASE_INSENSITIVE)

Match an email address

[\w.+-]+@[\w-]+\.[\w.-]+

Match a URL

https?:\/\/[\w.-]+(?:\.[\w.-]+)+[\w\-._~:/?#\[\]@!$&'()*+,;=]*

Match an IPv4 address

(?:(?:25[0-5]|2[0-4]\d|1\d{2}|[1-9]?\d)\.){3}(?:25[0-5]|2[0-4]\d|1\d{2}|[1-9]?\d)

Match an IPv6 address

(?:[A-Fa-f0-9]{1,4}:){7}[A-Fa-f0-9]{1,4}|::1|::

Match a UUID (v4)

[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}

Match a US phone number

(?:\+?1[-. ]?)?$?[2-9][0-9]{2}$?[-. ]?[2-9][0-9]{2}[-. ]?[0-9]{4}