Syntax and domain signals
Check email syntax without false verification claims
Extract email-shaped entries from a mixed list, then use the optional domain check to distinguish syntax failures from limited DNS signals.
Run the preloaded examples, open the result, then choose domain validation if you need domain-level DNS context.
Input and output
What to provide
- Paste one or many candidate strings with surrounding separators or notes.
- Domain checks are capped and run only after you explicitly request them.
What you receive
- Extraction returns strings that meet the selected syntax rules.
- Optional labels distinguish MX, address-record fallback, no DNS records and DNS errors.
Worked example
Example input
[email protected], missing-at.example.com
Expected output
[email protected]
How to use this workflow
- 1Paste candidate addresses.
- 2Run extraction to identify syntax-shaped matches.
- 3Optionally start domain validation from the result dialog.
- 4Interpret DNS labels using the displayed limitations.
Accuracy boundaries
- Syntax alone cannot verify mailbox existence.
- A domain with mail-related DNS can still reject a specific address.
- Temporary DNS errors and catch-all configurations limit interpretation.
Privacy for this mode
Candidate addresses are extracted locally. The optional DNS request sends only a limited set of unique domains to the server; analytics receives only coarse status-count buckets, never domains or addresses.
Read the full Privacy Policy →Troubleshooting
Syntax-shaped address excluded
Check spaces, punctuation and advanced filters against the original source.
DNS error
Retry later; treat it as unknown, not as proof that the mailbox is invalid.
Responsible use
Use the output as a review aid. Do not label people reachable, valid or consenting based only on syntax or DNS.
Review applicable privacy, anti-spam and data-protection requirements before contacting anyone.
Frequently asked questions
Does this verify a mailbox?
No. It checks syntax and, optionally, limited domain DNS signals.
What does MX found mean?
It means the domain publishes mail-exchange records; it says nothing conclusive about a specific mailbox.
Are full addresses sent for DNS checks?
The validation request uses unique domains, not complete email addresses.
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