Email Validator

About Email validator

This tool checks an email address in four separate layers: RFC 5322 syntax, whether the domain resolves in DNS, whether it publishes MX mail server records, and whether it appears on a list of disposable providers. Each layer reports pass, fail or skipped so you can see exactly where a problem sits.

How to use it

1. Type the address into the Email address field.
2. Select Validate. The address is sent to our server so it can run the DNS lookups.
3. Review the four Validation layers and their Pass, Fail or Skipped badges.
4. Open the Parsed address block to see the local part, domain and any punycode form.
5. Check the MX records table for the mail servers and their priorities.

Syntax failures are caught first

first..last@example.com

Syntax fails with the message Local part contains consecutive dots. The DNS, MX and disposable layers are shown as Skipped because there is nothing valid to look up.

When to use it

• Cleaning a signup list by finding addresses on domains that have no mail server.
• Understanding why a form library rejected an unusual but legal address, such as one with a quoted local part.
• Flagging throwaway addresses before they enter a newsletter or trial pipeline.
• Testing internationalized domains, which the tool converts to punycode for lookup.

Questions about Email validator

Does a passing result mean the mailbox exists?

No. All four layers describe the domain or the format, never the individual inbox. Only sending a message can confirm delivery, because providers rarely answer probing honestly.

What syntax limits are enforced?

The local part may be at most 64 characters, the domain 253 and the whole address 254. Dots cannot be consecutive or at the ends, and the domain needs a dot and an alphabetic top-level domain.

How complete is the disposable list?

It is a modest local sample of around sixty well-known providers plus their subdomains. A miss only means the domain is not on that list, not that it is permanent.

Why can a domain pass with no A record?

A domain that publishes MX records but no website address is legitimate, as many mail-only domains are set up that way. The tool reports it as resolving.

What about addresses with an IP in brackets?

Address literals such as user@[192.0.2.1] are accepted as valid syntax, but the DNS, MX and disposable checks are skipped because there is no domain name to look up.

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