Works with SendGrid

Spam Score Checker for SendGrid: Free Browser-Based Tool

Q: Is there a free way to spam-trigger analysis for SendGrid campaigns?

Yes. The MiN8T Spam Score Checker below runs entirely in your browser — no signup, no upload, and the output works with any SendGrid workflow.

→ Open the free Spam Score Checker

Browser-only, no signup, no upload. Output works with any SendGrid campaign.

Built by the MiN8T Engineering Team · Updated 28 May 2026

MiN8T Spam Score Checker interface preview

SendGrid'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 SendGrid

SendGrid's inbox-placement testing requires their Email Validation product (paid). External pre-send rule scoring is free and immediate.

Step-by-step: spam-trigger analysis for SendGrid

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 SendGrid

SendGrid-specific deliverability quirks to know

SendGrid's Marketing Campaigns and Transactional API serve different purposes. Pre-send rule analysis is essential for transactional flows where you control the HTML directly.

Frequently asked questions

Does SendGrid include a built-in spam score checker?

SendGrid provides basic functionality but lacks granular control. SendGrid's inbox-placement testing requires their Email Validation product (paid). External pre-send rule scoring is free and immediate.

Is there a free way to spam-trigger analysis for SendGrid 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 SendGrid.

What image size limit does SendGrid enforce?

SendGrid accepts uploads up to 2000 KB per image and recommends a max width of 600px for email body width. Supported formats: JPG, PNG, GIF, WebP.

Does SendGrid verify SPF, DKIM, and DMARC automatically?

SendGrid requires domain authentication (SPF + DKIM) via subdomain CNAME records. DMARC alignment is your DNS configuration.

What about subject line analysis for SendGrid?

SendGrid offers subject line A/B testing on Marketing Campaigns but no quantitative spam-trigger scoring. Use the free subject line analyzer for length scoring, spam-trigger detection, and sentiment analysis before pasting into SendGrid.

Related free tools

While preparing your SendGrid 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