What is an example of a matching and non-matching string?

A valid matching string is "developer@example.com". A non-matching string is "developer@.com".

Is this regex safe from ReDoS (Catastrophic Backtracking)?

Yes, this pattern is optimized for linear execution time and safe for browser-side validation without locking up the UI thread.

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Email Address Validation Regex

Q: How do I test this regex in JavaScript and TypeScript?

Use regex.test(): const regex = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/i; const isValid = regex.test(inputString);

Standard RFC-compliant email address validation pattern for form inputs.

Regular Expression Pattern:

/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/i

Valid Match Example:

developer@example.com

Invalid / Non-Match Example:

developer@.com

Regex Syntax Breakdown & Explanation

•^[a-zA-Z0-9._%+-]+ : Matches username with allowed email characters
•@[a-zA-Z0-9.-]+ : Matches domain name and subdomains
•\.[a-zA-Z]{2,}$ : Matches top-level domain extension (at least 2 letters)

Implementation in Popular Languages

JavaScript / TypeScript

const regex = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/i;
const isValid = regex.test("developer@example.com");
console.log(isValid); // true

Python (re)

import re

pattern = r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$"
match = re.match(pattern, "developer@example.com")
print(bool(match)) # True

Go (regexp)

package main
import (
  "fmt"
  "regexp"
)

func main() {
  re := regexp.MustCompile(`^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$`)
  fmt.Println(re.MatchString("developer@example.com"))
}

Frequently Asked Questions

Everything you need to know regarding specifications, syntax, and security best practices.

The regular expression pattern is /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/i. Standard RFC-compliant email address validation pattern for form inputs.