Establishing signal
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No signup required. Each tool runs the same checker engine that powers MailBaseline monitoring.
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A technical Gmail / Yahoo / Outlook requirements scan for your domain — SPF, DKIM, DMARC and MX, scored and explained. The same engine behind monitoring.
Scan a domainMore free tools
Counts your SPF record's DNS lookups against the RFC 7208 limit of 10 — with the full include trace.
Build a DMARC record with reporting enabled, ready to paste into DNS.
Verifies RFC 8058 List-Unsubscribe headers Gmail and Yahoo require for bulk mail.
Paste a received message's headers to verify SPF/DKIM/DMARC results and alignment end-to-end.
Setting up a specific platform? See the ESP setup guides.