Email DNS & DMARC tools
Email deliverability problems almost always trace back to DNS: an SPF record that doesn't include the right sending service, a DMARC policy set too strict too soon, or a DKIM selector that was never published. This page covers building and parsing SPF, DKIM, BIMI and DMARC records, checking a domain's live email DNS, building mailto links, and reading raw EML message files.
The SPF and DMARC builders work offline, generating a TXT record from rules you enter and flagging policy issues without querying DNS, while the DKIM / BIMI helper inspects a record you paste in the same way. The email DNS checker is the one tool that queries live MX, SPF, DMARC and DKIM records for a real domain, useful for confirming what's actually published versus what you intended. The EML viewer reads a saved message file locally, decoding its headers without needing a mail client.
6 tools
All Email Dev Tools tools
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DMARC record builder and parser
Build or parse DMARC records, then review alignment and policy choices
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DKIM / BIMI record helper
Inspect DKIM TXT records and draft BIMI values without DNS queries
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Email DNS checker
Query live MX, SPF, DMARC and DKIM records for email domains
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Email address and mailto builder
Build mailto links with recipients, subject and body encoding
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EML / MIME local viewer
Read EML MIME messages and inspect decoded headers without a mail client
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SPF record builder and static checker
Generate SPF TXT records from ordered sender rules with policy warnings
Email Dev Tools tools FAQ
SPF records are evaluated as an ordered list, and exceeding the 10 DNS lookup limit or omitting a service that sends on your behalf both cause failures. Build the record with the SPF record builder so the ordered rules and warnings are visible, then confirm what's actually published with the email DNS checker.
SPF lists which servers may send mail for a domain, DKIM signs messages cryptographically so recipients can verify they weren't altered, and DMARC tells receivers what to do when SPF or DKIM fail, plus how to report it. This page has a dedicated builder for each of the three records.
Yes — the EML / MIME local viewer parses the raw message file and shows decoded headers, body parts and attachments directly, which is useful when investigating a message outside of Outlook or Gmail. It reads the file locally and doesn't need a mail server or account.