What is the regex for strict url slug?

The regex pattern for strict url slug is `^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$`. This pattern validates strict slug: starts with letter, lowercase alphanumeric with dashes.

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/;` and test with `regex.test(yourValue)`. It returns `true` if the value matches.

How do I use this regex in Python?

In Python, use `import re; re.match(r'^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$', value)`. The raw string prefix (`r`) prevents Python from interpreting backslashes as escape characters.

Is this regex case-sensitive?

By default, yes. To make it case-insensitive, add the `i` flag in JavaScript (`/^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/i`) or use `re.IGNORECASE` in Python.

Regex for Strict URL Slug

Regex Pattern

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

Strict slug: starts with letter, lowercase alphanumeric with dashes

Quick Answer

The regex pattern for strict url slug is `^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$`. Strict slug: starts with letter, lowercase alphanumeric with dashes. This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
hello-world	✓ Matches
my-blog-post	✓ Matches
article1	✓ Matches
-leading	✗ No match
123-start	✗ No match
UPPER	✗ No match
trailing-	✗ No match

Code Examples

javascript

const regex = /^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/;
const isValid = regex.test(value);

python

import re
pattern = r'^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/', $value)) {
    echo "valid";
}

java

String pattern = "^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

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