A Chrome extension that fixes your messages & emails instantly — powered by free AI, zero tracking.
GrammarGenius Pro fixes grammar, tone, and spelling in your messages and emails with one click. It uses three free AI providers with smart priority-based fallback — if one fails or rate-limits you, the next kicks in automatically. No subscription. No server. No data collection. Just paste, fix, copy.
Designed for WhatsApp, Slack, Twitter, SMS, and any short-form text
| Action | What it does |
|---|---|
| Fix Message | Corrects grammar, spelling & punctuation with chosen tone |
| Shorten | Trims your message to the essential point |
| Expand | Adds detail and enriches the phrasing |
| Alternatives | Returns 2 rephrased versions to pick from |
| Changes Made | Shows a diff-style list of every correction applied |
Tones: 😊 Casual · 👔 Formal · 🤝 Friendly · 💪 Assertive
Designed for Gmail, Outlook, and professional correspondence
| Action | What it does |
|---|---|
| Fix Email | Full grammar, tone & structure correction |
| Rewrite | Complete email rewrite, same intent — better phrasing |
| Shorten | Condenses email without losing the message |
| Subject Line | AI-suggested subject line generated automatically |
| Smart Reply | Suggested reply drafted based on the email context |
Tones: 😊 Casual · 👔 Formal · 🤝 Friendly · 💪 Assertive · 🙏 Apologetic
Three free AI providers, tried in the order you set. If one fails, the next runs automatically.
| Priority | Provider | Model | Free Tier |
|---|---|---|---|
| configurable | 🟢 Groq | llama-3.3-70b-versatile |
✅ |
| configurable | 🔵 Google AI Studio | gemini-2.5-flash |
✅ |
| configurable | ⚫ GitHub Models | gpt-4o-mini |
✅ |
Provider #1 fails → tries #2 → tries #3. You set the order. One key is enough, three means near-zero downtime.
Robust response parsing — handles malformed JSON, code-fenced output, and partial responses from any provider without breaking.
- Clone or download this repo
- Open Chrome → go to
chrome://extensions - Enable Developer mode (top-right toggle)
- Click Load unpacked → select the project folder
-
Click the ✦ extension icon in your toolbar
-
Click ⚙ Settings in the top-right
-
Add a free API key for any provider(s):
Provider Where to get it Groq console.groq.com/keys Google AI Studio aistudio.google.com/apikey GitHub Models github.com/settings/tokens -
Use the 👁 eye icon to reveal/hide your key while typing
-
Set the priority (1st / 2nd / 3rd) for each provider
-
Click Save — that's it
Only one API key is required. Adding multiple gives you automatic fallback coverage.
- After fixing, click "↩️ Use This" to replace your input with the corrected version
- Click any Alternative phrasing to swap it into the result box
- CHANGES MADE shows a bullet list of every correction — great for learning
- The History panel in Settings lets you reload and re-fix previous inputs
- Toggle 🌙 / ☀️ in the header to switch between dark and light mode
- Input supports up to 10,000 characters with a live character counter
This extension requests only one browser permission:
"permissions": ["storage"]
storage— saves your API keys and preferences locally on your device- No analytics, no telemetry, no external tracking
- Your text is sent only to the AI provider API you configured — nothing else
- API keys never leave your browser except to authenticate with the respective provider
grammargenius-pro/
├── manifest.json # Extension manifest (MV3)
├── background/
│ └── background.js # Service worker — API proxy & fallback logic
├── popup/
│ ├── popup.html # Extension UI
│ ├── popup.css # Styles (dark/light theme, DM Sans font)
│ └── popup.js # UI logic, mode/tone/history management
└── assets/
└── icons/ # Extension icons (16 · 32 · 48 · 128px)
- Manifest V3 service worker architecture
- Zero build step — pure HTML/CSS/JS, load unpacked directly
- DM Sans typeface for a clean, modern UI
- chrome.storage.local for private, on-device persistence
MIT © GrammarGenius Pro