URL Theme Switcher by Ckrytech

URL Theme Switcher changes Firefox's theme color based on the site you are visiting. Pick a URL pattern, assign a color, and the browser chrome updates when a matching page opens.

• Theme color follows the URL rules you set
• Live preview while you choose a color
• Match a whole site, a path, or subdomains
• Rules are saved and applied automatically
• English, French, German, Chinese, and Japanese

• Development, staging, and production
• Work vs personal accounts
• Spotting a service at a glance (mail, GitHub, docs, and so on)

• example.com => every page on that host
• *.example.com => that host and its subdomains
• */dashboard/* => a specific path

1. Click the toolbar icon
2. Choose a pattern (whole site, this page, or subdomains)
3. Pick a color
4. Save the rule

No data collection. Rules stay in your browser. The add-on needs tabs (to read the current URL), storage (to save rules), and theme (to color the toolbar). It does not request access to website content. The project is open source.