--- title: "What is Client-Side Testing?" url: https://fibr.ai/glossary/client-side-testing description: "Learn what client-side testing is and how running experiments in the browser lets teams adjust layouts and messaging quickly without touching backend systems." last_updated: 2026-05-05T11:56:05.402810+00:00 --- Client-Side Testing tests variations of a webpage in the user's browser rather than on the server. It lets you adjust layouts, content, or elements in real time without touching backend systems. This approach is great for fast experiments, especially early in the optimization cycle. When you run client-side tests, you quickly see how users react to design or messaging changes without heavy engineering work. You can validate ideas faster, improve conversion points with agility, and refine the experience while keeping backend systems stable and untouched. ### Explore more Glossary terms ##### Customer Journey Mapping Customer Journey Mapping visualizes how customers move through stages like awareness, consideration, purchase, onboarding, and loyalty. Read More ##### Customer Journey Management Customer Journey Management focuses on designing, monitoring, and improving the end-to-end experience users have with a brand across channels. Read More ##### Customer Data Platform A Customer Data Platform (CDP) unifies data from multiple touch-points, such as websites, apps, CRM systems, and support tools into a single, persistent customer profile. Read More ##### Customer Acquisition Cost (CAC) Customer Acquisition Cost (CAC) measures how much a business spends to acquire one new customer, including marketing, sales, and sometimes onboarding expenses. Read More ##### Custom Conversion A custom conversion is a user-defined goal in analytics or advertising platforms used to measure specific actions that matter to a business. Read More ##### CUPED CUPED (Controlled Pre-Experiment Data) is a statistical technique used in experimentation to reduce variance and improve test sensitivity. Read More Delaware, USA Subscribe to our newsletter for exclusive updates and insights.