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Email Regex Tester

Test email validation regex patterns against a list of email addresses. Choose from preset patterns or write your own. See which emails match and which fail.

About this tool

Email validation regex is one of the most commonly needed patterns in web development, yet it is surprisingly difficult to get right. The official RFC 5322 spec allows characters that most people would not expect in an email address. This tool lets you test different regex patterns against a diverse set of test emails to find the right balance between strictness and permissiveness. Once you have validated your email addresses with regex, use our email validator for deeper DNS and MX record checks, and our disposable email checker to filter throwaway addresses.

Frequently Asked Questions

What is the best regex for email validation?

There is no single 'best' regex. For most applications, the simple pattern ^[^\s@]+@[^\s@]+\.[^\s@]+$ is sufficient. It checks for a local part, an @ symbol, and a domain with at least one dot. The HTML5 spec pattern is also a good choice since it matches what browsers validate.

Should I use regex for email validation?

Regex should be your first line of defense for format checking, but not your only validation. After regex, verify the domain has MX records, and ideally send a confirmation email. Over-strict regex rejects valid emails, while too-lenient regex lets obvious junk through.

Why is the RFC 5322 regex so complex?

RFC 5322 allows quoted strings, comments, folding whitespace, and other features that are technically valid but rarely used in practice. For example, "john doe"@example.com is technically valid. Most real-world applications can safely use a simpler pattern.

Can regex catch disposable email addresses?

You can add known disposable domains to a negative lookahead in your regex, but this approach is fragile since new disposable services appear constantly. Use our dedicated disposable email checker for more reliable detection. Regex is best for format validation only.

What about plus addressing (user+tag@gmail.com)?

Plus addressing is a valid email feature used by Gmail, Outlook, and others. Your regex should allow the + character in the local part. Rejecting plus addresses frustrates users who use it for filtering. The simple pattern ^[^\s@]+@[^\s@]+\.[^\s@]+$ correctly allows it.

How do I validate international email addresses?

International emails can contain Unicode characters in both the local part and domain (internationalized domain names). Standard ASCII-only regex will reject these. If you need to support international emails, use a more permissive pattern or validate with the browser's built-in email input type.

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