English
Free Email Marketing Tool
Analyze your email subject line in seconds. Get an instant score on length, power words, spam triggers, sentiment, and readability — optimize before you hit send.
Find the people & companies you need → Lessie AI
6 dimensions of subject line effectiveness, backed by email marketing research
Check character count, word count, and how your subject line appears on mobile devices. Stay under 60 characters for maximum visibility.
Identify emotional triggers, urgency words, and curiosity hooks that drive higher open rates across industries.
Detect words and patterns that trigger spam filters — like FREE, URGENT, all-caps, and excessive punctuation.
Measure the emotional tone of your subject line. Curiosity and excitement outperform neutral or negative sentiment.
Subject lines over 60 characters get truncated on mobile. Our tool flags lines that won''t display fully on iPhone, Android, and Gmail.
Detects ALL CAPS, excessive punctuation (!!!), and other formatting red flags that hurt deliverability. Pair with email verification for maximum inbox placement.
Type or paste the email subject line you want to test into the analyzer above.
Our engine checks length, power words, spam triggers, sentiment, readability, and formatting in under 2 seconds.
Apply the suggestions, adjust your subject line, and send your email with confidence. Use our cold email generator for AI-written alternatives.
Test every campaign subject line before hitting send. Optimize for open rates by checking length, power words, and spam triggers. Combine with Lessie''s email marketing tools for full campaign optimization.
Craft cold email subject lines that actually get opened. Avoid spam filters and use proven power words to boost reply rates. Pair with our email outreach tool for automated follow-ups.
Maximize subscriber engagement by testing subject lines for emotional impact and readability. Build your audience with verified contacts from targeted email lists.
A/B test subject line variations before spending on email campaigns. Use data-driven scoring to pick winners and improve open rates across every send.
