Inject custom JavaScript, CSS, and CDN resources into any website — with rule-based control.
Injectify is a free, open-source Chrome Extension (Manifest V3) that lets you run your own JavaScript, apply custom CSS, and load CDN libraries on any website you visit — all driven by a clean, rule-based configuration dashboard.
Whether you're a developer automating repetitive tasks, a designer tweaking third-party sites, or a power user who wants full control of their browsing experience, Injectify has you covered.
| Feature | Description |
|---|---|
| ⚡ JS Injection | Execute custom scripts on matching pages |
| 🎨 CSS Injection | Apply stylesheets per domain or globally |
| 📦 CDN Loading | Load external libraries (jQuery, lodash, …) before your code runs |
| 🎯 Flexible URL Patterns | Exact host · wildcard (*.example.com) · glob · RegExp |
| 🔀 Multiple Rules | Unlimited rules, toggle each independently |
| 💾 Import / Export | Backup & share rules as JSON |
| 🔒 Secure by Design | No eval(), no remote code execution |
| 🛠️ Manifest V3 | Built on Chrome's latest, most secure extension platform |
git clone https://github.com/shade-solutions/Injectify.git
# — or —
# Download ZIP from GitHub and extract it.- Open Chrome and navigate to
chrome://extensions - Enable Developer mode (toggle in the top-right corner)
- Click Load unpacked
- Select the
/extensionfolder inside the cloned repo
Injectify will appear in your extensions list. Pin it to the toolbar for easy access.
Injectify/
├── extension/ # Chrome extension source (load this folder)
│ ├── manifest.json # Manifest V3 config
│ ├── background.js # Service worker — storage & message routing
│ ├── content.js # Content script — injects JS/CSS/CDN
│ ├── popup.html/js/css # Toolbar popup (active rules at a glance)
│ ├── options.html/js/css # Full options dashboard
│ └── icons/ # Extension icons (16, 48, 128 px)
├── docs/ # Static landing page → GitHub Pages
├── assets/ # Source assets (SVG icon, …)
├── scripts/ # Dev utilities (icon generator, …)
├── .github/workflows/ # GitHub Actions (Pages deployment)
├── CONTRIBUTING.md
├── CODE_OF_CONDUCT.md
└── README.md
| Pattern | Matches |
|---|---|
* |
Every URL |
example.com |
Exact hostname (and sub-paths) |
*.example.com |
All subdomains of example.com |
https://example.com/* |
Glob / Chrome match-pattern style |
/github\.com\/user/i |
Full JavaScript RegExp with optional flags |
Each rule has the following fields:
| Field | Required | Description |
|---|---|---|
| Name | ✓ | Human-readable label |
| URL Pattern | ✓ | Pattern to match the page URL |
| Enabled | — | Toggle to enable / disable without deleting |
| JavaScript | — | Custom JS code to inject |
| CSS | — | Custom CSS to inject |
| CDN URLs | — | Array of external script URLs to load first |
- Chrome Web Store listing
- Firefox / Edge support
- Per-rule keyboard shortcut toggle
- Rule groups / folders
- Sync via
chrome.storage.sync - Dark mode for options page
- Regex pattern tester in the form
Have an idea? Open a feature request →
Contributions are very welcome! Please read CONTRIBUTING.md for setup instructions, PR guidelines, and code style notes.
# After cloning, install dev dependencies and generate icons
npm install
node scripts/generate-icons.js
⚠️ Warning: Injectify executes arbitrary JavaScript and CSS in the context of every page that matches a rule. Only install rules from sources you trust completely.
- Injectify does not use
eval()— scripts are injected via<script>elements - Injectify does not send your code anywhere — everything is stored locally in
chrome.storage.local - CDN URLs must begin with
http(s):// - User input is validated before saving
Please report security vulnerabilities privately via GitHub Security Advisories.
MIT © 2026 Shade Solutions