Email Validator

What the Email Validator Does

The Email Validator checks an address in two stages. First it tests the format against RFC 5322 rules to catch typos, missing at signs, and malformed domains. Then it queries live MX records through Cloudflare's DNS-over-HTTPS service to confirm that the domain is actually configured to receive email. Both results appear as a simple checklist with a clear valid or invalid verdict.

Single mode handles one address at a time, while bulk mode accepts a list with one address per line and validates everything at once in a results table. Lookups are cached per domain during your session, so checking many addresses at the same company only hits the network for the first one.

How to Use the Validator

1. Stay in Single mode and type an email address, or switch to Bulk and paste a list.
2. Press Validate Email or Validate All to run the checks.
3. Review the checklist in single mode, or the table of format, MX, and status results in bulk mode.
4. Addresses with a valid format and a domain MX record are marked Valid.

What Format Validation Catches

The RFC 5322 pattern rejects addresses without an at sign, addresses with spaces or double dots, domains without a dot, and illegal characters in the local part. It accepts the practical range of real world addresses, including dots, plus tags, and underscores. Format checking alone cannot tell you whether a specific mailbox exists, but it removes the majority of typos and copy and paste mistakes before you send anything.

What MX Validation Adds

A domain that cannot receive mail has no MX records. Querying them filters out addresses that look fine but point at parked domains, expired brands, or internal hostnames that do not exist on the public internet. A successful MX lookup proves the domain has at least one mail server willing to accept mail for it. It does not prove the individual mailbox is real, because that requires sending a message, which no privacy respecting tool should do without permission.

Related Tools

To inspect other DNS record types for the same domain, use the DNS Lookup tool, or compare results across global resolvers with the DNS Propagation Checker. To pull addresses out of a block of text before validating them, the Email Extractor collects unique addresses, and the Email Normalizer standardizes casing, dots, and plus tags. To build or test the pattern yourself, try the Regex Tester.