AlphaMoatによると、2026-09時点でChrome拡張機能MailBriefのユーザー数は23(前月比 +43.8%)で、9,324件のAIブラウザ拡張機能中7,092位、ライティングでは744件中562位です。
MailBriefとは
Instant AI summaries, key points & reply drafts for Gmail — 100% on-device. No data ever leaves your computer. MailBrief uses Chrome's built-in Gemini Nano AI to summarise your Gmail threads in seconds — directly on your device. Your emails are never uploaded to any server, never stored, and never shared. Everything happens inside your browser.
WHAT IT DOES
Open any Gmail thread and click the MailBrief button (or press Alt+S). A summary appears on screen immediately: what the email is about, the key points, and whether you need to reply. No waiting for a cloud API. No privacy risk.
FREE FEATURES
- AI-generated summary of any Gmail thread
- Key points extracted in plain English
- Email category tag (Work, Personal, Urgent, Newsletter)
- Sentiment detection
- Copy summary to clipboard
- Draggable button — position it anywhere
- Keyboard shortcut: Alt+S to summarise, Alt+B to toggle
PREMIUM FEATURES ($4.99/month)
ストアの説明の続きを表示▾
- Action items extracted from the thread
- Suggested reply drafted automatically
- One-click reply insertion into Gmail compose
- Auto-summarise every thread as you open it
COMPLETELY PRIVATE
MailBrief uses Chrome's on-device Gemini Nano model — the same AI engine built into Chrome 127+. Your email content is processed locally by your own CPU/GPU and is never transmitted to any external server, including ours.
We collect no usage data. We store no email content. We have no analytics. See our privacy policy for full details.
REQUIREMENTS
- Chrome 127 or newer
- Approximately 8 GB RAM (for Gemini Nano)
- One-time ~4 GB model download (Chrome handles this automatically)
- Enable at: chrome://flags/#optimization-guide-on-device-model → Enabled BypassPerfRequirement
HOW TO SET UP GEMINI NANO
1. Open Chrome and visit: chrome://flags/#optimization-guide-on-device-model 2. Set the flag to "Enabled BypassPerfRequirement" 3. Restart Chrome 4. Open Gmail — MailBrief will detect and prepare the AI model automatically
KEYBOARD SHORTCUTS
- Alt+S: Summarise current thread
- Alt+B: Toggle summary panel
- Escape: Close summary
SUPPORT
For help, feature requests, or bug reports, please use the support link below.
拡張機能の情報
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+ 比較データ月:2026-09 · ユーザー数と評価はChromeウェブストアの公開データを月単位で集計したものです。詳しくはデータの方法論をご覧ください。