Why deliverability matters
Even well-designed emails can end up in spam folders if they fail authentication checks, trigger spam filters, or are sent from blocklisted IP addresses. Deliverability reporting identifies these issues so you can fix them before sending to real recipients.
How it works
Deliverability reports are generated from messages captured in your Mailosaur inboxes. When you view a message in the message viewer, you can run a deliverability report from the sidebar. The report analyses the message and returns results across several categories.
What the report checks
| Category | What it checks |
|---|---|
| SPF | Whether the sending server is authorised to send on behalf of the domain |
| DKIM | Whether the email's digital signature is valid |
| DMARC | Whether the domain's DMARC policy is configured and the email passes |
| Blocklists | Whether the sending IP address appears on known spam blocklists |
| SpamAssassin | Spam score based on SpamAssassin rules |
| Content indicators | Known spam content patterns detected in the email |
| DNS configuration | Issues with A, MX, and PTR records for the sending domain |