Email authentication
SPF checker
Check an SPF record for the faults that silently break it, and count every DNS lookup it costs.
Email authentication
Check and build the SPF, DKIM and DMARC records that decide whether mail arrives.
Free SPF, DKIM and DMARC tools: check a domain, read every tag in plain words, and get the exact record to add. No account, nothing stored.
22 tools
Email authentication
SPF record generator
Build a valid SPF record from the senders you actually use, and see the DNS-lookup cost before you publish it.
Email authentication
DKIM checker
Find a domain’s DKIM key, read its tags in plain words, and flag a weak, revoked or malformed one.
Email authentication
DMARC checker
Read a DMARC record in plain words, and see exactly what a receiver does with mail that fails.
Email authentication
DMARC record generator
Build a DMARC record step by step, from monitoring through to full enforcement.
Email authentication
Email authentication report
See SPF, DKIM, DMARC and MX for one domain together, with the fixes in the order to do them.
Email authentication
Google Workspace setup checker
Check a domain’s MX, SPF and DKIM against the exact values Google Workspace documents.
Email authentication
Microsoft 365 setup checker
Check a domain’s Microsoft 365 SPF include and both DKIM selector CNAMEs, mistake by mistake.
Email authentication
Fastmail setup checker
Compare a domain’s MX, SPF and all three DKIM CNAMEs with the exact values Fastmail documents.
Email authentication
Zoho Mail setup checker
Confirm the SPF include Zoho documents, the zoho DKIM selector and Zoho’s mail hosts for a domain.
Email authentication
SPF flattening explainer
See how many of a domain’s SPF lookups flattening would actually remove, and what it costs to keep one flattened.
Email authentication
SPF record parser
Paste a draft SPF record and read it term by term, with the faults named, before anything is published.
Email authentication
DMARC record parser
Paste a DMARC record you are drafting and read every tag in it, with the syntax a receiver would discard it for.
Email authentication
Authentication-Results header explainer
Paste the Authentication-Results line off a message and read what every verdict in it means, including Microsoft’s compauth result and its three-digit reason code.
Email authentication
Email header analyser
Paste a raw email header block and read every Received hop, its delay and every SPF, DKIM and DMARC verdict in plain words.
Email authentication
DKIM key generator
Generate a DKIM keypair in your own browser and get the record to publish.
Email authentication
DMARC aggregate report reader
Read the RUA XML your mailbox provider emailed you by source IP, in this tab, without uploading it.
Email authentication
MTA-STS checker
Read a domain’s MTA-STS record and policy file, and check every mx pattern against its live MX records.
Email authentication
MTA-STS record and policy generator
Write both halves of MTA-STS at once: the _mta-sts TXT record and the policy file.
Email authentication
TLS-RPT record generator
Build the _smtp._tls record that asks senders to report failed TLS to your mail hosts.
Email authentication
BIMI checker
Read a domain’s BIMI record, check the SVG logo against Tiny PS, and whether DMARC lets it count.
Email authentication
BIMI record generator
Build the BIMI TXT record for your logo, with or without a certificate.