About the Email Validator
This validator checks each address against the syntax rules for email: a local part, an @, and a domain with a dot, using the widely adopted practical pattern rather than the full and rarely useful RFC grammar. Invalid addresses get a specific reason, missing @, no dot in the domain, a double dot, so you can see what is wrong. Addresses at well-known disposable domains are flagged.
The checks applied are these: exactly one @ separating a non-empty local part from a domain; no dot at the start or end of the local part and never two dots in a row; a domain made of dot-separated labels whose final label is at least two letters; and no spaces or control characters anywhere. The length ceilings apply too, 64 characters for the local part and 254 for the address as a whole.
Plenty of odd-looking addresses are perfectly legal and should survive a clean-up. Plus addressing such as kwame+receipts@example.com is valid and widely used, dots inside a Gmail local part are ignored by the provider yet still legal, and the long new top-level domains are fine. Rejecting any of these is the most common bug in hand-written validation.
Syntax validity does not mean an address exists or accepts mail; only sending to it proves that. Tidying a signup export before it goes into a mailing platform is the realistic use, and everything runs in your browser, so a customer list is not uploaded. To pull addresses out of text first, use Extract Emails.
How to use
- Paste addresses, one per line.
- Read valid or invalid with the reason for each.
- The status shows the valid count.
Common questions
- Does it check that the address exists?
- No. It checks syntax only. Existence can only be confirmed by sending mail.
- What is a disposable domain?
- A temporary-email service such as mailinator. Addresses there are flagged since they rarely belong to real users.
- Is my list uploaded?
- No. Validation runs in your browser.