EasySubs is a browser extension for language learning that enhances video watching on platforms like YouTube, Netflix, Coursera, and KinoPub. It provides interactive subtitles with translation capabilities, vocabulary export to learning services (Anki, LinguaLeo, Puzzle English), and UI customization features. The extension uses a content script to modify web pages, a background service worker for cross-tab communication, and a React-based popup for configuration. Built with React/TypeScript, Vite, and Effector for state management, it employs abstraction layers for video platforms, translation services, and learning integrations to handle the complexity of supporting multiple services with frequently changing UIs. The repository also includes a Next.js-based documentation site in the docs/ directory for marketing and user support.