Code Injector

Code Injector is a powerful userscript manager that lets you run custom JavaScript snippets and inject code on any website automatically or on demand.

KEY FEATURES

• Flexible URL patterns — match by exact domain, wildcard (*.example.com), path, port, or full URL. Use * to target all sites.

• Auto and manual modes — scripts run automatically on page load, or only when you click the ▶ button.

• Built-in code editor — full-featured editor with JavaScript syntax highlighting and real-time error detection.

• Fullscreen editing — expand the code editor to a fullscreen overlay for comfortable work on complex scripts.