Email Validator

What the validator checks

The check has two levels:

1. Syntax (RFC 5322). Catches typos like a missing @, double dots and invalid characters. It is a format check, not proof that the mailbox exists.
2. MX record present. Confirms the domain can accept mail. If the domain has no MX record, mail sent there bounces.

There is no third level: this validator does not send email and does not verify that a specific mailbox exists. Only a real test message proves that.

Syntax-level catches

A valid email has a local part, an @ and a domain part. The local part can include letters, digits, . _ + - and, in the quoted form, almost anything. Common real-world problems the syntax check rejects:

• Missing @ or multiple @
• Leading or trailing dot in the local part: .user@example.com
• Consecutive dots: user..name@example.com
• Spaces or other invalid characters in the local part
• Trailing whitespace or hidden Unicode characters from copy-paste

An address like user@localhost passes the syntax check (it is valid RFC), but a domain without a dot is usually not externally deliverable.

Common typo domains to watch for

A typo like gmial.com passes the syntax check, so read the domain line in the results yourself and compare it with this list.

What an MX record does and does not prove

An MX record says “this domain accepts mail at these servers”. It does not say that your specific address exists. Common caveats:

• Catch-all domains accept every address, so MX passes even for non-existent mailboxes.
• Greylisting can make some domains refuse the first lookup from unknown servers; a retry usually succeeds.
• Deliverability only shows up when you actually send. Use validators for obvious filtering, and measure deliverability through real campaigns with opt-in.

No email is sent

The check never sends an email to the address you enter. It is a format check plus a DNS lookup of the domain, nothing more.