browser-extension-developer

yamadashy's avatarfrom yamadashy

Use this skill when developing or maintaining browser extension code in the `browser/` directory, including Chrome/Firefox/Edge compatibility, content scripts, background scripts, or i18n updates.

⭐21.0kstars🔀963forks📁View on GitHub🕐Updated Jan 4, 2026
[Developer Tools]

When & Why to Use This Skill

The Browser Extension Developer skill is a specialized toolkit designed to streamline the creation, maintenance, and optimization of cross-browser extensions. Leveraging the modern WXT framework and Manifest V3, it provides a robust environment for managing content scripts, background processes, and multi-language support (i18n) across Chrome, Firefox, and Edge. This skill is essential for developers looking to build high-quality, compatible, and scalable browser-based tools with automated build and linting workflows.

Use Cases

  • 1. Cross-Browser Development: Efficiently build and maintain extensions for Chrome, Firefox, and Edge from a unified codebase using the WXT framework.
  • 2. Manifest V3 Migration: Seamlessly upgrade existing browser extensions to the latest Manifest V3 standards to ensure long-term compatibility and security.
  • 3. Global Localization (i18n): Manage and implement internationalization for over 12 languages, allowing for easy expansion into global markets.
  • 4. Web Page Enhancement: Develop and inject custom UI elements, such as buttons or overlays, into specific web platforms like GitHub to improve user workflows.
  • 5. Automated Build Pipelines: Utilize pre-configured commands for development, linting, and building production-ready files for multiple browser stores.
namebrowser-extension-developer
descriptionUse this skill when developing or maintaining browser extension code in the `browser/` directory, including Chrome/Firefox/Edge compatibility, content scripts, background scripts, or i18n updates.

Browser Extension Developer

Cross-browser extension (Chrome/Firefox/Edge) using WXT framework with Manifest V3. Injects "Repomix" button into GitHub repository pages.

Structure

browser/
├── entrypoints/       # background.ts, content.ts
├── public/_locales/   # i18n (12 languages)
├── wxt.config.ts      # WXT configuration
└── .output/           # Built files (chrome-mv3, firefox-mv2)

Commands

  • npm run dev - Development mode (Chrome default)
  • npm run dev:firefox - Firefox dev mode
  • npm run build-all - Build all browsers
  • npm run lint / npm run test

i18n

12 languages: en, ja, de, fr, es, pt_BR, id, vi, ko, zh_CN, zh_TW, hi

New language: Create public/_locales/[code]/messages.json with keys: appDescription, openWithRepomix

Notes

  • Chrome/Edge use chrome.* APIs, Firefox may need polyfills
  • Run lint and tests before completion