Subject Line Analyser

Want to boost your email open rates? It all starts with a great subject line.

This tool gives you instant feedback on your email subject line using proven best practices from Spotler and leading industry experts. Simply enter your subject line in the field below and receive:

  • A score out of 100
  • Quick, actionable feedback on what’s working (and what’s not)
  • Friendly pointers for improvement
  • Two rewritten alternatives you can A/B test
  • A professional review, just like you’d get from an in-house email expert

No fluff. No distractions. Just a focused review of your subject line.

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Throughout 2025, we've been testing everything over email, landing pages and social. Think subject lines, CTA buttons, page layouts, social hooks and more.

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