Chrome Extension

Stop sending emails
nobody opens.

EmailSubjectScore Pro is a free Chrome extension that scores Gmail subject lines for spam risk, clarity, and urgency in real time. AI-powered rewrite suggestions when your score is weak.

Also known as: Gmail subject line tester, email subject line score, subject line analyzer, subject line grader — all inside Gmail compose, no tab switching.

Install Free — Chrome Web Store

Free · 50 scores/month · No signup

EmailSubjectScore Pro scoring a subject line in Gmail

How it works

1

Open Gmail compose

Start writing an email as normal. The scoring panel appears automatically.

2

See your scores

Spam risk, clarity, and urgency update live as you type your subject line.

3

Rewrite if needed

Click "Suggest rewrite" for AI-optimized alternatives. Copy to clipboard — you decide what to use.

Features

🛑

Spam Detection

Flags trigger words and patterns that send your email to spam or promotions tab.

🔍

Clarity Score

Evaluates whether your subject line makes a specific, actionable promise.

⚡

Urgency Rating

Balances urgency cues without being spammy. Too much urgency = spam filter.

✨

AI Rewrite

One-click AI-optimized alternatives. Copy to clipboard — never auto-modifies your email.

Frequently asked questions

Is EmailSubjectScore Pro free?
Yes. 50 AI scores per month, no signup, no credit card. Structural scoring (spam trigger detection) is always unlimited.
What data does it collect?
Only anonymous device ID for rate limiting. Subject line text is sent to Azure OpenAI for scoring but processed ephemerally — never stored. Image and page content never leave your browser.
Does it work with Google Workspace?
Yes. Works with personal Gmail and Google Workspace accounts. The extension activates in any Gmail compose window.
Does it auto-modify my emails?
Never. AI rewrite suggestions are copy-to-clipboard only. You paste what you want. The extension never changes your email content.
How is it different from SendCheckIt or CoSchedule?
EmailSubjectScore Pro scores inside Gmail as you type — no tab-switching or copy-pasting into external tools. It also provides AI rewrite suggestions, not just a score.

Score your next subject line.

Free to install. Takes 2 seconds. No signup needed.

Install Free — Chrome Web Store

How we compare

vs Sendcheckitvs CoSchedulevs Automizyvs TouchStonevs Zurb TestSubject

What is EmailSubjectScore Pro?

EmailSubjectScore Pro is a free Chrome extension that scores Gmail subject lines for spam risk, clarity, and urgency in real time. It runs inside the Gmail compose window and offers AI-powered rewrite suggestions when a subject line scores weak. Free tier includes 50 AI scores per month, no signup, no credit card.

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