Get AI-powered scores and optimization suggestions to improve your email open rates - analyze length, emotional impact, spam risk, and more
Overview
Key benefits
Get individual scores (0-100) for length optimization, emotional impact, spam risk, personalization, urgency, and clarity. Each dimension comes with specific feedback explaining why you scored high or low, helping you understand what to improve.
Based on analysis of millions of email campaigns, the AI predicts your likely open rate. This helps you set realistic expectations and compare different subject line options quantitatively before choosing which to send.
Don't just get a score - get specific advice. The tool tells you exactly what to change: 'Shorten by 10 characters,' 'Add personalization token,' 'Remove spam word X,' 'Increase urgency with deadline mention.' Every suggestion is actionable and specific.
Can't think of a better subject line? The AI generates 3-5 alternative versions optimized for higher open rates. Each alternative addresses weaknesses in your original while maintaining your core message and brand voice.
Avoid the dreaded spam folder. The tool identifies specific words and phrases that trigger spam filters across Gmail, Outlook, Yahoo, and other major email providers. Replace flagged terms before sending to ensure inbox delivery.
Select your industry (e-commerce, SaaS, B2B, etc.) and get benchmarks and advice specific to your market. What works for e-commerce flash sales differs from B2B thought leadership emails, and the AI understands these nuances.
How it works
Type or paste the email subject line you want to test. You can test subject lines for campaigns you're about to send, or generate multiple options and test each one to find the winner.
Include your email preview text (the snippet that appears after the subject line in inboxes). The AI considers how subject and preview text work together since recipients see both when deciding whether to open.
Choose your industry from the dropdown. This ensures benchmarks and recommendations are relevant to your specific market - e-commerce subject lines should be different from enterprise B2B.
Get instant analysis across 6 dimensions: length, emotional impact, spam risk, personalization, urgency, and clarity. Each score includes an explanation of what you did well or poorly in that category.
The AI identifies specific strong points to maintain and weak points to improve. This qualitative feedback helps you understand the 'why' behind your scores and learn subject line best practices.
Apply the specific suggestions to improve your subject line, or choose from the AI-generated alternatives that score higher. Test multiple versions if you're A/B testing your campaign.
Use cases
Scenario
An e-commerce marketer has written subject lines for their weekly promotional email but wants to ensure maximum open rates before sending to 100,000 subscribers.
Solution
Test each subject line option, compare predicted open rates, and select the highest-scoring version. The small time investment in testing can result in thousands of additional opens and significantly more revenue from the same campaign.
Scenario
A email marketing manager wants to A/B test subject lines but needs to start with two strong options rather than one good and one bad option that wastes half the send.
Solution
Generate and test multiple subject line variations. Select the two highest-scoring options with different approaches (e.g., one focused on urgency, one on curiosity) for a meaningful A/B test that will produce actionable insights.
Scenario
A company notices their emails are increasingly landing in spam folders and suspects their subject lines might be triggering spam filters.
Solution
Run all subject lines through the spam risk checker before sending. Identify and remove spam trigger words, adjust formatting, and reduce excessive punctuation or ALL CAPS to improve inbox delivery rates.
Scenario
A marketing director wants to train their team on writing better subject lines but needs an objective way to provide feedback on team members' drafts.
Solution
Have team members test their subject lines and review scores together. Use the specific feedback to teach principles: why certain lengths work better, how personalization impacts opens, what emotional triggers resonate with your audience.
Best practices
Test before sending, not after - it only costs 1 credit and could dramatically improve campaign performance
Consider preview text as part of the package - subject line and preview text work together in the inbox
Don't just chase a perfect score - a 95 that sounds robotic might perform worse than an 85 that sounds human
Test multiple variations if you're unsure - compare scores to make data-driven decisions
Pay special attention to spam risk score - even a great subject line is useless if it lands in spam
Industry matters - don't use e-commerce tactics for B2B audiences or vice versa
Personalization helps, but only if accurate - [First Name] with wrong names hurts more than it helps
Balance urgency and anxiety - URGENT works for deals, not for most informational emails
Learn from your results - note patterns in what scores well for your audience and replicate success
Update regularly - email best practices evolve; what worked last year may not work today
More capabilities
FAQ
By industry
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