Works with Postmark
Spam Score Checker for Postmark: Free Browser-Based Tool
→ Open the free Spam Score CheckerBrowser-only, no signup, no upload. Output works with any Postmark campaign.
Postmark's built-in tools cover the basics, but the spam score checker workflow often benefits from a dedicated, browser-only preprocessor before uploading. Pre-send spam-trigger analysis catches issues before they impact your sender reputation. Free rule-based scoring combined with a Naive Bayes classifier identifies precisely which content triggers fire.
Why pre-process before uploading to Postmark
Postmark's spam-scoring is post-send via SpamAssassin. Pre-send rule scoring catches issues before the message ever hits their servers.
Step-by-step: spam-trigger analysis for Postmark
- Paste your campaign HTML into the free spam score checker below
- 60+ rules evaluate subject patterns, body keywords, header completeness, link density, HTML structure, image-to-text ratio, and authentication signals
- A Naive Bayes classifier trained on 50,000+ labeled messages provides a complementary spam-probability score
- Review the rule-by-rule breakdown and fix triggers before sending via Postmark
Postmark-specific deliverability quirks to know
Postmark is transactional-only. Pre-send rule analysis matters because transactional emails are time-critical and a deliverability issue stops user flows immediately.
Frequently asked questions
Does Postmark include a built-in spam score checker?
Postmark provides basic functionality but lacks granular control. Postmark's spam-scoring is post-send via SpamAssassin. Pre-send rule scoring catches issues before the message ever hits their servers.
Is there a free way to spam-trigger analysis for Postmark campaigns?
Yes. The free MiN8T Spam Score Checker runs entirely in your browser — no signup, no upload, no rate limits. The output is a standard file you can upload directly to Postmark.
What image size limit does Postmark enforce?
Postmark accepts uploads up to 5000 KB per image and recommends a max width of 600px for email body width. Supported formats: JPG, PNG, GIF, WebP.
Does Postmark verify SPF, DKIM, and DMARC automatically?
Postmark requires SPF and DKIM via DNS verification. They strongly recommend DMARC with p=quarantine or stricter.
What about subject line analysis for Postmark?
Postmark does not offer subject line analysis. External tools fill this gap for transactional templates. Use the free subject line analyzer for length scoring, spam-trigger detection, and sentiment analysis before pasting into Postmark.
Related free tools
While preparing your Postmark campaign, you may also want:
- Image Compressor — also free, browser-based, optimized for email marketers
- GIF Compressor — also free, browser-based, optimized for email marketers
- CSS Inliner — also free, browser-based, optimized for email marketers
- Inbox Preview — also free, browser-based, optimized for email marketers
Spam Score Checker also works with
