Username Regex Pattern

Live Regex Tester

Pattern Breakdown

Code Examples

const regex = /^[a-zA-Z0-9_-]{3,20}$/;
const test = "cool_user123";
console.log(regex.test(test)); // true

// Extract matches
const matches = test.match(regex);
console.log(matches);

import re

pattern = r'^[a-zA-Z0-9_-]{3,20}$'
test = "cool_user123"
match = re.search(pattern, test)
print(match)  # Found!

package main

import (
    "fmt"
    "regexp"
)

func main() {
    re := regexp.MustCompile(`^[a-zA-Z0-9_-]{3,20}$`)
    fmt.Println(re.MatchString("cool_user123")) // true
}

Common Use Cases

Match Examples

About the Username Regex

Validates usernames with letters, numbers, underscores, and hyphens. Length 3-20 characters.

Regular expressions (regex) are powerful pattern matching tools used across virtually all programming languages. The username pattern is classified as beginner difficulty in the text & strings 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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