22 free tools
Email authentication
Check and build the SPF, DKIM and DMARC records that decide whether mail arrives.
The tools
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.
SPF checker
Check an SPF record for the faults that silently break it, and count every DNS lookup it costs.
Live checkSPF record generator
Build a valid SPF record from the senders you actually use, and see the DNS-lookup cost before you publish it.
In your browserDKIM checker
Find a domain’s DKIM key, read its tags in plain words, and flag a weak, revoked or malformed one.
Live checkDMARC checker
Read a DMARC record in plain words, and see exactly what a receiver does with mail that fails.
Live checkDMARC record generator
Build a DMARC record step by step, from monitoring through to full enforcement.
In your browserEmail authentication report
See SPF, DKIM, DMARC and MX for one domain together, with the fixes in the order to do them.
Live checkGoogle Workspace setup checker
Check a domain’s MX, SPF and DKIM against the exact values Google Workspace documents.
Live checkMicrosoft 365 setup checker
Check a domain’s Microsoft 365 SPF include and both DKIM selector CNAMEs, mistake by mistake.
Live checkFastmail setup checker
Compare a domain’s MX, SPF and all three DKIM CNAMEs with the exact values Fastmail documents.
Live checkZoho Mail setup checker
Confirm the SPF include Zoho documents, the zoho DKIM selector and Zoho’s mail hosts for a domain.
Live checkSPF flattening explainer
See how many of a domain’s SPF lookups flattening would actually remove, and what it costs to keep one flattened.
Live checkSPF record parser
Paste a draft SPF record and read it term by term, with the faults named, before anything is published.
In your browserDMARC record parser
Paste a DMARC record you are drafting and read every tag in it, with the syntax a receiver would discard it for.
In your browserAuthentication-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.
In your browserEmail 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.
In your browserDKIM key generator
Generate a DKIM keypair in your own browser and get the record to publish.
In your browserDMARC aggregate report reader
Read the RUA XML your mailbox provider emailed you by source IP, in this tab, without uploading it.
In your browserMTA-STS checker
Read a domain’s MTA-STS record and policy file, and check every mx pattern against its live MX records.
Live checkMTA-STS record and policy generator
Write both halves of MTA-STS at once: the _mta-sts TXT record and the policy file.
In your browserTLS-RPT record generator
Build the _smtp._tls record that asks senders to report failed TLS to your mail hosts.
In your browserBIMI checker
Read a domain’s BIMI record, check the SVG logo against Tiny PS, and whether DMARC lets it count.
Live checkBIMI record generator
Build the BIMI TXT record for your logo, with or without a certificate.
In your browser
More free tools
Every other family, and what it checks.
DNS
Read what a domain is really publishing, and build the records a provider asks for.
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14 toolsFor developers
Try a webhook, a key or an API call without writing a script to do it first.
10 toolsMessaging
Work out what a text message really costs to send.
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Work out what to charge, what it leaves you, and what a change mid-cycle costs.
17 tools
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