Back to Content Creation & Optimization
Content Creation & Optimization

Subject Line Tester

Test email subject lines for length, spam triggers, personalization, and emoji usage with detailed scoring and optimization tips.

Email Subject Line

46 characters

Subject Line Best Practices

What Works

  • • Keep it 30-50 characters (optimal length)
  • • Use personalization tokens ({firstName})
  • • Add 1-2 relevant emojis for visual appeal
  • • Create urgency without being spammy
  • • Test multiple variations
  • • Front-load important words

What to Avoid

  • • ALL CAPS text (looks spammy)
  • • Excessive punctuation (!!!, ???)
  • • Spam trigger words (FREE, urgent, act now)
  • • Too many emojis (3+)
  • • Generic, boring copy
  • • Misleading clickbait

Learn More in The Course

This tool is derived from Module 1 of "The Ultimate Growth Engineering Course." Learn the complete experimentation framework, how to design better tests, and interpret results like a pro.

Explore the Course