The benchmark compared the performance of major headless browser automation tools, including Puppeteer, Playwright, WebDriverIO with DevTools and Selenium, and Cypress. The study aimed to inform future choices for synthetic monitoring and testing through data-backed comparisons. Cypress was found to exhibit a longer startup time compared to other tools in short execution scenarios, but its performance improved when running multiple tests sequentially, closing the gap with other tools like Playwright. The final ranking showed Puppeteer as the fastest tool across all scenarios, followed by Playwright, with Cypress showing significant improvement in longer suites. The study highlights the importance of considering the specific use case and tool features when choosing an automation tool for synthetic monitoring and testing.