Regex for Email Validation — Pattern Explained with Examples

Email validation is one of the most common regex use cases in web forms and user registration systems. This pattern checks for the basic structure of an email address: a local part, the @ symbol, and a domain with at least one dot-separated subdomain and a valid top-level domain.

The Pattern

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

Pattern Breakdown

Matches

• user@example.com
• first.last@company.co.uk
• user+tag@domain.org
• 123@test.io
• name@sub.domain.com

Does NOT Match

• @example.com
• user@.com
• user@com
• user@domain
• user space@domain.com
• user@domain..com

Language Examples

JavaScript

const emailRegex = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
console.log(emailRegex.test('user@example.com')); // true
console.log(emailRegex.test('@example.com'));      // false

Python

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

PHP

$pattern = '/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/';
var_dump(preg_match($pattern, 'user@example.com')); // int(1)
var_dump(preg_match($pattern, '@example.com'));      // int(0)

Common Pitfalls

• Overly strict regexes reject perfectly valid emails with plus tags or subdomains
• Very permissive patterns allow inputs like user@com with no TLD dot separation
• Unicode email support varies — this pattern only covers ASCII
• The only truly reliable way to validate an email is to send a confirmation message

Real-World Use Cases

• User registration forms — ensure signups provide a properly structured email address
• Contact forms — validate user input before sending an automated reply
• Data import cleaning — filter invalid email entries from CSV or database exports

FAQ

Related Patterns

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