Domain Name Regex Pattern
Validates domain names with proper label formatting, supporting subdomains and various TLD lengths.
Live Regex Tester
Pattern Breakdown
Code Examples
JavaScript
const regex = /^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$/;
const test = "sub.example.com";
console.log(regex.test(test)); // true
// Extract matches
const matches = test.match(regex);
console.log(matches);Python
import re
pattern = r'^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$'
test = "sub.example.com"
match = re.search(pattern, test)
print(match) # Found!Go
package main
import (
"fmt"
"regexp"
)
func main() {
re := regexp.MustCompile(`^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$`)
fmt.Println(re.MatchString("sub.example.com")) // true
}Common Use Cases
Match Examples
| Input | Result |
|---|---|
| sub.example.com | Match |
| -invalid.com | No Match |
About the Domain Name Regex
Validates domain names with proper label formatting, supporting subdomains and various TLD lengths.
Regular expressions (regex) are powerful pattern matching tools used across virtually all programming languages. The domain name pattern is classified as intermediate difficulty in the validation category. It works in all major programming languages.
When using this regex, always consider edge cases and test thoroughly with real-world data. Use the interactive tester above to validate the pattern against your specific inputs before deploying to production.
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Frequently Asked Questions
What is the Domain Name regex pattern?
Validates domain names with proper label formatting, supporting subdomains and various TLD lengths.
How do I use the Domain Name regex?
Use the pattern /^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$/ in your code. In JavaScript: new RegExp('^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$', ''). Test it above with your own input.
What does this Domain Name regex match?
This pattern matches: "sub.example.com". It does NOT match: "-invalid.com". DNS validation, URL parsing, domain registration checks.
Is the Domain Name regex beginner-friendly?
This pattern is rated Intermediate. It uses some advanced features like character classes and quantifiers.
What languages support the Domain Name regex?
This pattern works in all major programming languages including JavaScript, Python, Java, C#, Go, Ruby, PHP, and more. Syntax may vary slightly between regex engines.
Can I modify the Domain Name regex for my use case?
Yes! Use the interactive tester above to modify the pattern and test with your own data. Common modifications include making it case-insensitive (add 'i' flag), matching globally (add 'g' flag), or adjusting character classes.