The subject line decides whether your outreach or newsletter gets opened. This tester checks the four factors you control: character length (20–55 keeps it whole on mobile), word count, spam-trigger words that hurt deliverability, and shouting signals like ALL-CAPS and stacked exclamation marks.
Aim for 20–55 characters (mobile-safe)
3–9 words performs best
None found ✓
All-caps hurts deliverability
OK
It runs entirely in your browser and updates as you type, so you can iterate until every check is green. Pair it with the outreach email generator for a complete pitch.
Build a personalized pitch email in three tones.
0–100 headline score with concrete improvement hints.
From list size to projected revenue and ROI.
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