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About Email Validator Online
This tool validates an email address by checking its syntax against the RFC 5322 specification and by verifying that the domain has valid MX (mail exchanger) records. Both checks must pass for the address to be considered deliverable.
Syntax validation catches typos like missing @, malformed local parts, and disallowed characters. MX validation catches domains that look valid but have no mail server configured — like "@gmial.com" or a recently expired domain. Together they catch the vast majority of fake or fat-fingered addresses.
Use it during signup form validation, before sending a bulk email campaign to clean addresses out of your list, or when debugging deliverability issues with a specific recipient.
How to use this tool
How to syntax-check a single email address
Enter the email
Drop the address into the "Email" field. The tool trims whitespace and lowercases the result before testing — display variations don't matter.
Press Run
Result returns `valid` (boolean) plus `reason` if false. The matcher uses a pragmatic regex (one `@`, at least one `.` in the domain, no spaces) — strict RFC 5322 quoted-locals and IP-literal hosts aren't accepted, but those are <0.01% of real-world addresses.
What `valid: true` doesn't prove
Syntax-validity is necessary but not sufficient. It does NOT prove the mailbox exists, the domain has MX records, or the user reads it. For a deliverability check, send a confirmation email or use mx-lookup + a real SMTP probe — never a regex.
Common false-positives
`a@b` passes naive checks but fails because the domain has no dot. `foo@bar.` is rejected here for the trailing dot. Plus-addressing (`name+tag@gmail.com`) is valid and the tool accepts it; that's working as intended.