PagePatch — Custom CSS & JS

Inject custom CSS and user scripts into pages that match your URL rules.

PagePatch is a Chrome extension for customizing web pages and browser identity through URL-based rules. It is designed for users who want to adjust page appearance, run custom scripts, test websites with different User-Agent values, or add personal enhancements to specific websites. You can create independent rules for different websites, subdomains, and URL paths, then combine any of the following: Add multiple remote CSS resources and load them in a defined order. Write inline CSS to change layouts, fonts, colors, or hide unwanted elements. Add multiple remote JavaScript resources or write custom JavaScript. Run scripts in either an isolated environment or the page environment. Configure a separate User-Agent for each rule. Apply the same User-Agent to selected third-party request domains. Use exact domains or *.example.com wildcard allowlists. Update the User-Agent sent in network requests and the value exposed through navigator.userAgent. Remove related UA Client Hint headers so requests do not continue exposing the original browser identity. PagePatch also includes rule filtering, quick enable/disable controls, a toolbar badge showing matching rules, SPA URL change support, light and dark themes, Chinese and English interfaces, and keyboard shortcuts for saving. Rules and interface preferences are stored locally in Chrome. PagePatch runs only on websites configured and authorized by the user. User-Agent changes require a manual page reload to take full effect.