Server-side rendering (SSR) is a technique where a web server generates the initial HTML for a page before sending it to the browser. This allows users to see content more quickly and can improve the performance, reliability, and speed with which search engines index a page. After the page loads, JavaScript typically hydrates the HTML to make it fully interactive.
For software testers, server-side rendering introduces a distinction between content being visible and the application being ready for interaction. A page may appear complete while event listeners and client-side logic are still loading. Understanding SSR helps testers recognise hydration-related failures and avoid assuming that a visible element is immediately ready for automation.
