Email Deliverability Tester

Instantly test SPF, DKIM and DMARC using a unique email address.

Generate a unique test address, send an email, then view a permanent results page.
Check authentication and content signals to help improve inbox placement.

Your unique test email address

9e2ad21c62be5fca608edb6c431e611faf18@mail-tester.co.uk

View results page

Send an email to the address above. Once received, refresh the results page.

What we check

SPF

Pass/fail (rspamd or headers)

DKIM

Signature result (if present)

DMARC

Alignment + policy result

Content

Size, links, images, attachments, text/HTML balance

Note - Authentication can pass even if the content is low quality. Content score handles that separately.

Email Deliverability FAQs

How does Mail-Tester.co.uk work?

We generate a unique test address. Email it, then view a permanent results page with authentication and content signals.

What do you check?

We check SPF, DKIM and DMARC signals, key headers and sender IP, plus content factors like links, size, images and attachments.

Why can SPF, DKIM and DMARC pass but emails still hit spam?

Authentication proves identity, but inbox placement also depends on sending reputation, content quality, sending patterns and recipient engagement.

Need help improving deliverability? Run a test, then use the help form on the results page.

Learn more about how this tool works on our About page. See Terms for usage and limitations.

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