Mail tester
Send one email to a test address and get a 10-point score for authentication, spam filters, blacklists, content and links.
Each address takes one email and gives you a report on it. You get 3 tests a day.
Mostly clean
Grade BExampleScores 8.4 out of 10 (grade B). 1 thing to look at below, worst first.
Needs attention
1 finding, worst first.8 passed, 2 for informationNothing to do here. Open it to see the detail.SPF passes for northwind-outbound.comDKIM passes for northwind-outbound.comDMARC passes for northwind-outbound.comReverse DNS matchesNot on any of 12 blacklistsSpamAssassin: 1.2 of 5rspamd: -1, no actionAll 2 links loadShowHide
Authentication
As the receiving server saw it.Spam filter rules
SpamAssassin 1.2 of 5. rspamd -1, no action. Positive points push toward spam.Blacklists
The IP that delivered your email, checked against public DNS blacklists.Links
2 in the message, each followed to where it ends.Headers
The ones filters read most.This is an example for a fictional sender. Get a test address above to score your own email.
Next
What the mail tester does
DNS checks show how a domain is set up. The mail tester shows what happens to a real message. The page gives you a unique test address. Send your email to it from the inbox and the tool you use for campaigns, and you get a report on what arrived, scored out of 10.
The report covers SPF, DKIM and DMARC as the receiving server saw them, ARC and BIMI, SpamAssassin and rspamd scores with every rule that fired, blocklist status for the sending IP and domains, the links and content of the message, and its headers.
How to run a useful test
- Send the real campaign email, not a message that says 'test'. Content is a large part of what gets scored.
- Send it from the same inbox and the same sending tool as the campaign, so the authentication and the sending server match.
- Fill in merge fields with a real example. A raw {{first_name}} looks broken to a filter and to a person.
- Test each sending setup on its own. Another inbox or another tool can give a different result.
Each IP address gets 3 tests a day, enough to test, fix and test again.
How to read the score
Start with authentication. If SPF, DKIM or DMARC fails here, fix that before anything else, because no content change makes up for it. Then read the SpamAssassin and rspamd rules. Each one names a specific trigger, like an HTML part with no plain-text version, a link through a URL shortener or a missing Message-ID header.
SpamAssassin marks a message as spam at a score of 5.0 by default, so a message well under that is clean by its rules. That's still one filter's view. Gmail and Outlook use their own filters and your sending history, so 10 out of 10 here doesn't promise the inbox. A low score is a clear sign something needs fixing.
Why it matters for cold email
Cold email breaks in ways DNS can't show. A sequencer that rewrites links through a shared tracking domain, a signature with a heavy image, a tool that signs DKIM with its own domain instead of yours. All of these look fine in DNS and show up as soon as a real message is checked.
Run a test whenever something in the chain changes: a new inbox, a new sending tool, a new tracking domain or a new template.