EmailSubjectScore Pro — Subject Line Scorer for Gmail

Score your Gmail subject lines as you type — spam, clarity, urgency rated live, with one-click AI rewrite.

Every cold email, sales outreach, and important message lives or dies by its subject line. EmailSubjectScore Pro is a free Chrome extension that scores your Gmail subject lines in real time as you type — rating spam risk, clarity, and urgency on clear scales. When your score needs work, one click generates AI-powered rewrite suggestions that beat your original. Stop guessing and start sending subjects that get opened. ### How it works 1. Open Gmail and click Compose 2. Type your subject line — scores appear automatically after a brief pause 3. See three color-coded ratings: Spam (0-100), Clarity (0-10), Urgency (0-10) 4. Click "Suggest rewrite" for 3 AI-generated alternatives 5. Click "Use this" to replace your subject instantly, or copy to clipboard 6. Send with confidence ### Features - Real-time subject line scoring inside Gmail compose — no tab switching - Three-axis scoring: Spam risk, Clarity, and Urgency - AI-powered rewrite suggestions that improve on your original scores - Color-coded score badges (green/yellow/red) for instant feedback - Works with Gmail light and dark mode - 50 free scores per month (10 per day) — no signup required - Lightweight: under 60KB, no slowdown - Privacy-first: subject text is processed ephemerally, never stored ### What we DON'T do - We never read your emails — only the subject line you type - We never track opens, clicks, or recipients - We never store your subject lines on our servers - We never sell your data - No account required for the free tier ### Why not Boomerang / Mailtrack / ChatGPT for Gmail? - Boomerang Respondable scores subjects but costs $15/mo and doesn't suggest rewrites - Mailtrack tracks opens but doesn't score subjects at all - ChatGPT for Gmail generates text but doesn't score against a structured rubric - EmailSubjectScore Pro does both — score AND rewrite — free to start (50 scores/month) ### Built for cold emailers, sales reps, and founders If you send important outbound emails from Gmail — sales outreach, recruiting, fundraising, freelance pitches — your subject line is the gate. EmailSubjectScore Pro is the quality check before you hit Send. ### From an indie developer EmailSubjectScore Pro is built by a solo developer who sends cold emails too. No bloated sales suite, no enterprise pricing, no feature creep. One job: score your subject line and help you improve it. Questions or feedback? Shoot me a support request .