Template for Creating Chromium-based Web Browser Theme

Template repository for customizing your browsing experience by designing your unique Chromium-based web browser theme from scratch.

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Install

Get it from web store(s)

Install it manually

First, download the latest released ZIP file from the releases section and save it to your computer. Then, unzip the file and follow the instructions below, which may vary slightly depending on your browser:

• To access the Extension Management page, visit the following URL: chrome://extensions. You can also open the Extension Management page by clicking on your browser's menu and selecting Extensions -> Manage Extensions.

• To enable "Developer mode," select the option located at the top right corner of the page.

• Click the Load unpacked button, then find the directory where you extracted the release and select it.

• The theme should now be active in your browser. To remove the theme, access your browser's theme or appearance settings and select a different one.

List of Chromium-based Web Browsers

Browser	Tested	Theme Supported	Browser Developer
Google Chrome	✅	✅	Google
Microsoft Edge	✅	✅	Microsoft
Ungoogle Chromium	✅	✅	Slimjet
Vivaldi	🔴	☑️	Vivaldi Technologies
Opera	🔴	☑️	Opera Software
Brave	🔴	☑️	Brave Software

• ✅ Tested/Supported

• ☑️ Should work in theory

• 🔴 Not Tested

Note

This theme uses Manifest V3 to ensure compatibility with the latest Chromium extension standards.

A sample of the manifest.json file containing all supported properties.

{
  "author": "I am Programmer <[email protected]>",
  "description": "Chrome theme by I am Programmer",
  "icons": {
    "128": "image/store_icon_128x128.png"
  },
  "manifest_version": 3,
  "name": "Simple Theme",
  "short_name": "simple_theme",
  "theme": {
    "colors": {
      "control_background": [0, 0, 0],
      "control_button_background": [0, 0, 0],
      "background_tab": [0, 0, 0],
      "background_tab_inactive": [0, 0, 0],
      "background_tab_incognito": [0, 0, 0],
      "background_tab_incognito_inactive": [0, 0, 0],
      "bookmark_text": [0, 0, 0],
      "button_background": [0, 0, 0],
      "frame": [0, 0, 0],
      "frame_inactive": [0, 0, 0],
      "frame_incognito": [0, 0, 0],
      "frame_incognito_inactive": [0, 0, 0],
      "ntp_background": [0, 0, 0],
      "ntp_header": [0, 0, 0],
      "ntp_link": [0, 0, 0],
      "ntp_link_underline": [0, 0, 0],
      "ntp_text": [0, 0, 0],
      "ntp_section": [0, 0, 0],
      "ntp_section_link": [0, 0, 0],
      "ntp_section_link_underline": [0, 0, 0],
      "ntp_section_text": [0, 0, 0],
      "omnibox_background": [0, 0, 0],
      "omnibox_text": [0, 0, 0],
      "tab_background_text": [0, 0, 0],
      "tab_background_text_inactive": [0, 0, 0],
      "tab_background_text_incognito": [0, 0, 0],
      "tab_background_text_incognito_inactive": [0, 0, 0],
      "tab_text": [0, 0, 0],
      "toolbar": [0, 0, 0],
      "toolbar_button_icon": [0, 0, 0],
      "toolbar_text": [0, 0, 0]
    },
    "images": {
      "theme_frame": "images/theme_frame.png",
      "theme_frame_inactive": "images/theme_frame_inactive.png",
      "theme_frame_incognito": "images/theme_frame_incognito.png",
      "theme_frame_incognito_inactive": "images/theme_frame_incognito_inactive.png",
      "theme_frame_overlay": "images/theme_frame_overlay.png",
      "theme_frame_overlay_inactive": "images/theme_frame_overlay_inactive.png",
      "theme_toolbar": "images/theme_toolbar.png",
      "theme_ntp_background": "images/theme_ntp_background.png",
      "theme_tab_background": "image/theme_tab_background.png",
      "theme_tab_background_incognito": "images/theme_tab_background_incognito.png",
      "theme_tab_background_inactive": "images/theme_tab_background_inactive.png",
      "theme_tab_background_incognito_inactive": "images/theme_tab_background_incognito_inactive.png",
      "theme_ntp_attribution": "images/theme_ntp_attribution.png",
      "theme_button_background": "images/theme_button_background.png",
      "theme_window_control_background": "images/theme_window_control_background.png"
    },
    "tints": {
      "background_tab": [0, 0, 0],
      "buttons": [0, 0, 0],
      "frame": [0, 0, 0],
      "frame_inactive": [0, 0, 0],
      "frame_incognito": [0, 0, 0],
      "frame_incognito_inactive": [0, 0, 0]
    },
    "properties": {
      "ntp_background_alignment": "bottom",
      "ntp_background_repeat": "repeat",
      "ntp_logo_alternate": 1
    }
  },
  "version": "1.0.0",
  "version_name": "simple_theme_v1.0.0"
}

Important

Chromium has discontinued the use of "ntp_section," but it still utilizes it as a fallback option for "ntp_header" in order to support legacy themes.

{
 "theme": {
   "colors": {
     "ntp_section": [0, 0, 0],
   }
 }
}

Please remove all unused properties from the manifest.json file. If you use images, make sure that the image file exists at the path and that the image dimensions are correct.

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🧰 Resource

• The list of properties supported by the Chromium browser has been extracted from this source.

  • https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/themes/browser_theme_pack.cc

• Theme Creation Guide By Patrick Batenburg

  • https://github.com/Patrick-Batenburg/GoogleChromeThemeCreationGuide

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💕 Credits

• I am Programmer @iamprogrammerlk

  iamprogrammer.lk 🔸 [email protected] 🔸 x.com/iamprogrammerlk 🔸 youtube.com/@iamprogrammerlk

• Contributors

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✨ Get Involved

Get in touch with the project developers and the community through our GitHub Discussions forum. View contributing.md for information.

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🔥 Issues

Bug reports and feature requests can be submitted on the Github Issues.

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👍 Code of Conduct

This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Code of Conduct, Security Policy, and be bound by the terms of the Contributor License Agreement.

Important

This project is not a platform for discussing politics, social issues, race, religion, gender, or sexual orientation. Please keep those discussions elsewhere.

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⚖️ License

This work is distributed under the MIT License License.

See license for more information.

Permissions

• ✅ Commercial use
• ✅ Distribution
• ✅ Modification
• ⛔ Patent use
• ✅ Private use

Conditions

• ⛔ Disclose source
• ✅ License and copyright notice
• ⛔ Network use is distribution
• ⛔ Same license
• ⛔ State changes

Limitations

• 🚫 Liability
• ⛔ Trademark use
• 🚫 Warranty

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©️ Copyright

• Copyright © 2025 🇱🇰 I am Programmer @iamprogrammerlk.
• Copyright © 2025 ❤️ Contributors.

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