How can you test spam score before sending?
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You've written a great campaign, you're ready to hit send, and then you wonder: will this actually reach the inbox? Testing your spam score before sending is how you find out before your subscribers do.
Here's a practical workflow that covers the main layers worth checking.
Start with Mail-Tester
Mail-Tester is free and takes about two minutes. It gives you a unique address. You send your actual campaign (or a close draft) to that address, then visit the site to see your score out of 10. Anything 8 or higher is a healthy result. Below 7, you'll see exactly what dragged you down, things like missing authentication, suspicious links, or content flags.
The score itself is a SpamAssassin score in disguise. SpamAssassin assigns points for rule violations, and the total determines whether a filter blocks or passes your message. A SpamAssassin score of 5.0 or higher typically triggers a spam flag, so lower is better on that scale. Mail-Tester flips it so higher is better, which is easier to read.
Check your authentication first
Before worrying about content, make sure your SPF, DKIM, and DMARC records are all passing. Authentication failures add significant points to your spam score and no amount of clean copy fixes a broken record. Mail-Tester shows auth results right in its report.
Add inbox placement testing for critical sends
GlockApps goes a step further than a score. It sends your email to real seed mailboxes at providers like Gmail, Outlook, and Yahoo, then tells you how many landed in the inbox, how many hit spam, and how many went to promotions tabs. A good spam score doesn't always mean inbox placement. Knowing the difference matters more than most people realise. (This distinction is covered in more depth in the spam score vs. placement test question.)
What to actually look at in the results
- Authentication status. SPF, DKIM, and DMARC should all pass. Any failure here is fix-first territory.
- SpamAssassin score. Aim for under 2.0. Between 2.0 and 5.0 is a yellow flag. Above 5.0 is a red one.
- Blocklist hits. If your sending IP or domain is on a blocklist, your score almost doesn't matter. You can run a quick check with our free blocklist checker.
- Link analysis. Shortened URLs, redirect chains, or links pointing to flagged domains all raise your score.
- HTML structure. Badly coded HTML, excessive image-to-text ratios, or hidden text can all trigger filter rules.
For developers and high-volume senders
Running a local SpamAssassin instance lets you test messages directly from your build pipeline and see exactly which rules fired. It takes setup, but it's worth it if you're sending at scale and want to catch issues before a campaign ever touches your ESP.
Speaking of which, many ESPs have a built-in spam check in their send flow. It's worth using, but treat it as a first pass, not a final verdict. It won't tell you about placement or blocklists.
Still if you're unsure how to read what comes back, our SOS hotline is free and we'll walk you through it.
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