Local files, live websites
Map a site hostname to a local JavaScript file, CSS file, or both. Your latest saved code runs on every matching visit.
Free, open-source browser extension
Inject local JavaScript and CSS into any website
Connect local code files to the sites where you need them. Kode Injector applies your JavaScript and CSS automatically on every visit — no more pasting the same snippet into DevTools after each reload.
- ✓ Free & open source
- ✓ No account
- ✓ No analytics
- ✓ 30 interface languages
A faster feedback loop
Your code stays local. The result appears on the page.
Rules you can control
Create, edit, duplicate, pause, and delete rules without repeatedly pasting snippets into DevTools.
Pause at any level
Toggle one file, every rule for the current site, or all injection globally from the options page and toolbar popup.
Built for real workflows
Test a fix, automate a repetitive check, adjust a live layout, or compare local code against staging and production.
Three steps
From local file to live page
Install the extension, create a rule for a hostname, then reload the target page. Your configured files are applied automatically.
Follow the complete setup guide →- 01
Choose a site
Enter a hostname such as
example.com. - 02
Select local code
Add a
file:///JavaScript path, CSS path, or both. - 03
Reload
Open the matching website and your code runs automatically.
Made for practical work
One tool, three kinds of workflow
Developers
Run local utilities and work-in-progress code against pages you do not control.
QA engineers
Keep repeatable checks and diagnostics available across reloads and test environments.
Designers
Preview CSS adjustments on a live interface without rebuilding or editing the source site.
Local by design
No developer-operated backend or analytics
Rules, preferences, file paths, and local file contents stay on your device. Kode Injector reads only files you configure and applies them only to matching websites. Selected code becomes available to that page, so use trusted code on trusted sites.
No advertising or profiling
No developer-operated server
Rules remain in browser storage
Native Helper is read-only
Stop re-pasting code after every reload
Add Kode Injector to Chrome, connect a local JavaScript or CSS file, and keep your testing loop moving.