Puppeteer is a high-level Node.js library for browser automation, primarily targeting Chrome/Chromium and Firefox. It provides a rich API to control browsers programmatically via the Chrome DevTools Protocol (CDP) and WebDriver BiDi, supporting both headless and headed modes. The library is organized as a monorepo with multiple packages: `puppeteer` (full library with browser management), `puppeteer-core` (core automation API without browser download), `@puppeteer/browsers` (browser download and CLI), `@puppeteer/ng-schematics` (Angular integration), and a test server. The architecture features abstract API classes (Page, Browser, ElementHandle) with separate CDP and BiDi implementations, a custom event system, and extensive use of TypeScript generics and resource management patterns. Puppeteer is widely used for end-to-end testing, web scraping, and automation tasks, with a strong emphasis on cross-browser compatibility and modern web platform features.