We fed Zenie AI hundreds of thousands of email subject lines with above 60% open rates to get you the ultimate, free subject line tester!
Our AI subject line tester analyzes your email subject lines against several key factors that affect your open rates, including length, personalization, spam triggers, and FOMO elements. Simply enter your subject line and receive an instant health score based on data from hundreds of thousands of high-performing emails with open rates of 60% or higher.
Zenie AI has been trained on email subject lines that achieved open rates above 60% across millions of inboxes. Unlike generic tools, our subject line tester provides actionable insights on spam triggers, optimal word count, emoji usage, and personalization opportunities to maximize your email performance.
Yes, our AI subject line analyzer is completely free with no credit card required. You can test unlimited subject lines and access all scoring features. For advanced email marketing automation and campaign building, you can try our full platform free for 14 days.
Yes. Our free subject line tester specifically checks for common spam trigger words, such as "free," "guaranteed," "act now," and "urgent." It also analyzes capitalization patterns, excessive punctuation, and other factors that commonly cause emails to be directed to spam folders.
Our subject line analyzer recommends 4-6 words for optimal mobile display, with a total range of 4-9 words for maximum impact. The tool automatically flags subject lines that are too long or too short and provides suggestions for improvement based on successful email campaigns.
Feedback:
Flag these words and suggest safer alternatives.