Mail Tester

Send a real email to a test address and get a score out of 10. The report checks SPF, DKIM and DMARC, reverse DNS, spam signals, links, unsubscribe headers and HTML, and says how to fix each problem.

What the test checks

Authentication: SPF, DKIM and DMARC results, and whether DKIM and the return path match your From domain.
Sending server: Reverse DNS for the sending IP, and the Message-ID and Date headers.
Content: Spam filter verdict, spam phrases, one-click unsubscribe, a plain-text part, and size against Gmail's 102 KB clip.
Links and images: Empty, placeholder and relative links, and images without alt text.
Compatibility: HTML and CSS that Gmail, Outlook, Apple Mail or Yahoo do not render.

We read the message to build the report and delete it after. The report keeps the sender, the subject and the results, not the body. Each address takes one message, and you can start 3 tests a day.

Send emails with confidence

SMTPfast sets up SPF, DKIM and DMARC for your sending domains and adds one-click unsubscribe to broadcasts.

Get Started Free