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Email Subject Tester
Score subject lines for mobile length and spam triggers before you hit send.
- 1Fill inputs
- 2Run
- 3Copy / export
Inputs
Required fields on the left
Results
Appears after you run
Inbox before send
Check mobile length and common spam triggers before you ship the campaign.
From inputs to a decision
Score subject lines for mobile length and spam triggers before you hit send.
- 01
Paste subjects (one per line).
- 02
Review scores and warnings.
- 03
Rewrite flagged lines and re-test.
Tips for better results
- Keep critical words in the first ~35 characters for mobile previews.
- Paste the final draft you would publish — not a rough outline.
- Run humanizer or voice checks after scoring headlines and subjects.
Frequently asked questions
- Why flag “Re:” and “Free”?
- They are common spam and preview-spoof patterns. Use them only when intentional.
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