Extro

Created by Bartosz Zagrodzki, this starter kit eliminates months of configuration by providing battle-tested patterns for authentication, storage, messaging, and deployment across Chrome and Firefox browsers. The template features full TypeScript type safety across extension pages and backend services, support for all extension page types including popup, options, background workers, content scripts, and side panels, authentication and OAuth integration powered by Supabase, storage and messaging APIs for cross-context communication, hot module replacement for instant feedback during development, pre-configured CI/CD pipelines for automated testing and deployment, internationalization (i18n) support for multi-language extensions, analytics integration for tracking user behavior, and modern development tooling with Biome for fast linting and formatting. Unlike starting from scratch with browser extension APIs, Extro provides proven patterns for handling complex scenarios like cross-origin messaging, persistent storage across extension contexts, authentication flows within extension constraints, and building multiple extension pages that share code efficiently.

This starter is invaluable for developers building productivity extensions who want to focus on features rather than boilerplate, indie developers launching browser extensions as products, teams creating internal tools as browser extensions, developers migrating from Manifest V2 to V3, and anyone frustrated with the complexity of browser extension development. The opinionated stack means less decision fatigue while maintaining the flexibility to customize for specific needs. Extro demonstrates how to architect modern browser extensions with proper separation of concerns, integrate backend services with extension frontends, implement authentication within extension security constraints, and deploy extensions to both Chrome Web Store and Firefox Add-ons.