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Validation

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Regex for Hex Color

A simple validator for 3- or 6-digit hex colors, useful in design tooling and theme settings.

Regex

/^#?(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/

Try this pattern

Matches current input

Test text

#0fa

1 match found in the current text.

Passing examples

#0fa
3366FF

Failing examples

#abcd
rgb(0,0,0)

Code examples

JavaScript

const regex = /^#?(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/g;
regex.test(input);

Python

import re
pattern = re.compile(r"^#?(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{6})$")
bool(pattern.search(input))

Go

re := regexp.MustCompile("^#?(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{6})$")
matched := re.MatchString(input)

Related Validation Patterns

Regex for Valid Email Address

/^[^\s@]+@[^\s@]+\.[^\s@]+$/i

Regex for URL Slug

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

Regex for Strong Password

/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[^A-Za-z\d]).{12,}$/

Regex for UUID v4

/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i

Regex for IPv4 Address

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

Regex for Semantic Version

/^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?(?:\+[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?$/