At Mailpro, we use SpamAssassin to evaluate every campaign before it goes out — both the email content and the sender's reputation, including the IP address. Each test assigns points; once the total crosses a threshold (typically 5 or 6), the message is flagged as spam.
The good news: most spam-score issues are easy to fix. Use the checklist below to dramatically improve your inbox placement.
1. Pass Email Authentication (SPF, DKIM, DMARC)
Authentication is the single biggest factor SpamAssassin checks. Misconfigured records can add several points instantly.
- Configure your SPF record to authorize Mailpro to send from your domain.
- Set up DKIM so each email is cryptographically signed.
- Add a DMARC policy to align SPF and DKIM signatures.
Not sure where to start? Our email deliverability hub walks you through every record step by step.
2. Avoid Spammy Content
- Steer clear of typical spam keywords ("free", "easy money", "100% guaranteed"). See our list of spam words to avoid.
- Don't write entire emails in capitals or use excessive exclamation marks.
- Watch out for special characters and currency symbols in your subject line.
- Keep attachments clean — avoid unusual or executable file types.
3. Clean Up Your HTML
- Don't paste from Word — it generates bloated markup that SpamAssassin penalizes.
- Never send an email made of a single image. Keep a healthy text-to-image ratio.
- Use a real plain-text version (Mailpro generates one automatically for every campaign).
4. Protect Your Sender Reputation
- Send from a domain you own — not gmail.com, yahoo.com or another free provider.
- Keep your IP reputation high by mailing engaged contacts only.
- Never buy or rent contact lists. Always confirm subscriptions with double opt-in.
5. Test Before You Send
Mailpro includes a built-in anti-spam scoring tool that runs SpamAssassin on your draft and shows you exactly what to fix — before a single contact receives your message.
Stop landing in spam — start landing in inboxes
Mailpro's deliverability infrastructure handles authentication, IP reputation and spam testing for you. Create your free Mailpro account or talk to our deliverability team.
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