📧 Email Subject Line A/B Tester & Spam Trigger Checker
Test and optimize your email subject lines before sending. Detect spam trigger words, preview mobile truncation, compare A/B variants, and improve open rates with 100% client-side privacy.
Why is email subject line length important?
Most mobile email clients (like iPhone Mail and Gmail app) truncate subject lines after 40-50 characters. Keeping your subject line concise ensures the main value proposition is visible without being cut off.
What are spam trigger words?
Spam trigger words are words or phrases that email service providers (ISPs) like Gmail, Outlook, and Yahoo flag as suspicious (e.g., '100% free', 'make money fast', 'act now'). Using them increases the risk of your email landing in the Spam folder.
Is my email marketing content kept private?
Yes! All analysis, spam word checking, and length calculations are processed entirely within your web browser. No data is sent or stored on any server.
