Writing signals, not inbox predictions.
The analyzer reviews characteristics of the subject line itself, including length, capitalization, punctuation and selected wording patterns.
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Email Subject Line Analyzer
Review subject-line length, readability, punctuation, capitalization and practical wording signals before your next send.
BROWSER-LOCAL ANALYSIS
Analyze your subject line
This analysis runs in your browser. The subject line is not sent to InboxAI merely to calculate this score.
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PREPARATION SCORE
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This is a writing heuristic, not a deliverability or inbox-placement prediction.
Your analysis will appear here.
Enter a subject line to review length, readability, punctuation, capitalization and selected wording signals.
Your subject stays in the browser.
The score is calculated locally in this page. InboxAI does not need the subject line to be uploaded to a diagnostic service for this analysis.
No tool can guarantee inbox placement.
Delivery and placement depend on sender reputation, authentication, content, audience quality, provider systems and recipient behaviour.
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Use the score as preparation guidance
A strong subject-line score does not mean a campaign will reach the inbox or perform well. Always evaluate the audience, sender, message and campaign context together.
RUN THESE CHECKS IN YOUR WORKFLOW
Prepare the message, sender and campaign together.
InboxAI is building toward an email-operations workflow where useful preparation and deliverability checks sit closer to the campaign itself.