Free email authentication tools
Check your DMARC, SPF and DKIM records, generate correct ones, and trace any message from its header. No sign-up, and every tool runs in your browser.
- Six tools, all free
- Nothing stored
- Explained in plain language
Runs the DMARC checker, which covers all four records at once.
Check, build and investigate
Three checkers, two generators and a header analyser.
_dmarcDMARC checker
Check DMARC, SPF, DKIM and MX in one pass, with a plain-language verdict.
Open the toolv=spf1SPF checker
Validate your SPF record, count DNS lookups and map every include.
Open the tool_domainkeyDKIM checker
Find DKIM keys at common selectors and check their length and flags.
Open the toolp=rejectDMARC generator
Build a valid DMARC record with every option explained.
Open the toolinclude:SPF generator
Combine every sending service into one SPF record under the limit.
Open the toolReceivedEmail header analyser
See if a message passed SPF, DKIM and DMARC, and where it was delayed.
Open the toolWhich tool do I need?
- Not sure where you stand? The DMARC checker tests DMARC, SPF, DKIM and MX together.
- SPF failing or over 10 lookups? Use the SPF checker, then rebuild it with the SPF generator.
- Publishing DMARC for the first time? The DMARC generator builds the record.
- Suspicious email or slow delivery? Paste its header into the header analyser.
What a record check cannot see
- Records show what you published. Only DMARC aggregate reports show who actually sends as your domain.
- A clean result today can change the day someone adds a new email service.
- Enforcement at p=reject should rest on weeks of report evidence, not a single check.
About the tools
What they do, what they keep, and where they stop.
Are these tools really free?
Yes. There is no sign-up and no usage limit. A quick check is the first step toward protecting a domain, and when you want that work done for you, MailMarq manages it.
Do you store the domains or headers I check?
No. DNS lookups go from your browser straight to public resolvers run by Google and Cloudflare, and headers are parsed on the page itself. Nothing you type is sent to MailMarq.
Which tool should I start with?
Start with the DMARC checker. It checks DMARC, SPF, DKIM and mail servers together and tells you which problem to fix first. The other tools go deeper on one part each.
How are these different from MXToolbox and similar tools?
They cover the same core record checks, with results explained for business owners rather than administrators, and without adverts. The SPF tools follow every nested include and count lookups the way receivers do.
What can a record check not tell me?
A record check shows what you published, not who is sending as you. Only DMARC aggregate reports reveal every server using your domain, legitimate or not. That evidence is what a safe move to p=reject has to rest on.
Want it done for you?
Our free assessment reviews your DMARC, SPF and DKIM, maps the services sending as you, and tells you plainly what it would take to reach enforcement. No charge and no obligation.