Email Validator

Validate email addresses with syntax check and format verification.

Frequently Asked Questions

What is validated?

Basic RFC 5322 syntax validation. For DNS MX validation, server-side checking is required.

Can I bulk validate?

Bulk validation feature is planned for future updates.

Anatomy of a Valid Email Address

An email address has two parts separated by@: the local part (before @) and the domain (after @). The full format is defined by RFC 5321 and RFC 5322.

┌─────────────── local part (max 64 chars)
|             ┌────── domain label (max 63 chars)
|             |      ┌─── TLD (2+ chars)
alice.smith+tag@company.com
                         |
                         └── Total max length: 254 characters

Common Email Validation Rules

RuleValidInvalid
Must contain exactly one @user@example.comuser@@example.com
Local part 1–64 charsa@b.comxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx@b.com
Domain must have a TLDuser@example.comuser@example
No consecutive dotsuser@mail.example.comuser..name@example.com
No leading/trailing dot in localuser@example.com.user@example.com
+tags are validuser+filter@gmail.comN/A

Syntax Validation vs Deliverability Verification

Syntax validation (what this tool does) checks that the address is formatted correctly according to RFC 5322. It cannot confirm that the address actually exists or can receive email.

Deliverability verification requires additional server-side checks:

  • MX record lookup — confirms the domain has mail servers.
  • SMTP handshake — connects to the mail server to check if the mailbox exists (without sending email).
  • Catch-all detection — some domains accept all addresses; SMTP checks will always return valid.

For list hygiene in production, use a service like ZeroBounce, NeverBounce, or Mailgun's Email Validation API which performs all three checks.