✉️ Subject Line Tester

Paste your subject line. We'll analyze length, emojis, trigger words, and predict open-rate impact.

0 characters · 0 words 📱 0 chars on mobile preview

💡 Subject line best practices

  • 30-60 characters ideal; 40-50 sweet spot. Mobile cuts at ~30 chars.
  • Avoid ALL CAPS — even one word fully capitalized hurts.
  • One emoji max in subject — more triggers filters.
  • Specificity beats hype: "5 launch lessons from week 1" > "Amazing tips!!!"
  • Personalize when relevant: first name in subject lifts opens 5-15%.
  • Skip trigger words: FREE, URGENT, GUARANTEE, $$$, 100%.
  • Test multiple versions — A/B testing subject lines has the highest ROI of any email optimization.