Arjun introduces Playwright, a library for cross-browser end-to-end testing of web applications. The challenges in modern web testing include the evolving web platform and reactive frameworks. Playwright provides capable, reliable, and fast automation, with the ability to capture events and enhance test reliability. It uses browser contexts for faster execution and supports multiple languages and frameworks. Playwright is used by companies like VS Code, Bing, Adobe, and material UI, and offers cross-browser support and an improving roadmap.