Puppeteer is a modern JavaScript library used for browser automation, primarily for Chrome and Chromium, utilizing the Chrome DevTools Protocol to perform tasks such as web scraping, UI testing, and PDF generation. Built for Node.js, Puppeteer operates in headless mode by default but can be configured to display a browser window, and it now supports Firefox in experimental mode via the WebDriver BiDi protocol. Setting up Puppeteer involves installing Node.js, npm, and Puppeteer itself, with an option to use puppeteer-core for independent browser management. LambdaTest, a cloud-based platform, is recommended for running Puppeteer tests at scale, offering the advantages of real desktop browsers and parallel test execution. Despite some cross-browser limitations, Puppeteer's robust configuration and automation capabilities make it a valuable tool for developers.