Regex for Domain Name

javascript

const regex = /^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$/;
const isValid = regex.test(value);

python

import re
pattern = r'^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$/', $value)) {
    echo "valid";
}

java

String pattern = "^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\\.)+[a-zA-Z]{2,}$";
boolean isValid = value.matches(pattern);