What the deliverability score measures
The score adds up five weighted checks that receivers actually run when your message arrives. SPF is worth 25 points, DKIM 20, DMARC 20, blacklists 20 and MX 15. Partial credit reflects real-world impact: a DMARC record at p=none earns half the DMARC points because it is required but enforces nothing, and an SPF record near the lookup limit loses a few points because it is one include away from breaking.
Domain existence and website presence are reported but not scored. They do not affect authentication directly, yet a domain with no site and no MX looks disposable to both filters and the humans reading your email. Treat them as hygiene items on every outreach domain.
- 90 to 100: excellent, send with confidence.
- 75 to 89: good, tighten the flagged items.
- 55 to 74: needs work, some mail will go to spam.
- Below 55: at risk, fix before sending anything.
The order to fix things in
Start with anything listed on a blacklist, because a listing overrides everything else. Next, make sure the domain has MX records pointing at your mailbox provider so replies and bounces arrive. Then publish SPF with your provider's include, enable DKIM in the provider and publish the key, and finally add DMARC starting at p=none with a rua address.
Re-run the check after each DNS change. Records normally propagate within minutes on modern DNS hosts, though a long TTL on an old record can delay it. Once every check passes, tighten DMARC to quarantine and later reject.
yourdomain.com TXT v=spf1 include:_spf.google.com ~all
google._domainkey TXT v=DKIM1; k=rsa; p=MIIBIjANBg...
_dmarc TXT v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.comWhy a perfect score does not guarantee the inbox
Authentication and reputation records are the entry ticket. Once past them, Gmail and Microsoft weigh engagement: opens, replies, deletes without reading and spam complaints. A brand-new domain with flawless DNS still needs warm-up, sensible daily volume per mailbox, a clean list and copy that earns replies rather than deletions.
For agencies and SDR teams that means spreading sends across several domains and mailboxes, keeping each mailbox to a modest daily limit and retiring domains that accumulate complaints. InboxOne provisions domains with all of these records already in place and monitors them continuously, so the technical layer stays fixed while you focus on the campaign.
Checking secondary and lookalike domains
Cold email is usually sent from secondary domains so the main brand domain is never at risk. Each of those domains needs the full set of records, not just the primary. Run this check on every domain in rotation, including ones you have paused, because a domain with broken DMARC or a lapsed DKIM key quietly hurts the sender reputation of the whole operation.
- Use a domain that clearly relates to your brand, with a site that redirects to the main one.
- Give every secondary domain its own SPF, DKIM and DMARC records.
- Check blacklists weekly and pause a domain the moment it is listed.
- Keep the primary domain out of cold outreach entirely.
