Email Subject Line Tester

Paste a subject line and get an instant score with tips to boost your open rate.

What makes a good subject line?

The best subject lines are short (around 30-50 characters), clear, and specific - they tell the reader what's inside without hype or spam-trigger words. Avoid ALL CAPS, too many exclamation marks, and words like "free", "winner" or "urgent" that trip spam filters.

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