Monitoring website performance is crucial for developers, especially those using the Jamstack architecture. The average website loading time of 3 seconds or more can lead to user abandonment. Amazon's findings show that every 100ms of latency costs 1% in sales. To measure performance, developers need tools such as Netlify, Eleventy.js, and the browser monitoring agent. The New Relic One browser monitoring agent measures webpage build times and reports back to the dashboard in real-time, providing information on code causing delays. By setting up a web application with these tools, developers can monitor their website's performance and detect issues before they arise. This includes measuring organic user interactions, generating simulated traffic using synthetic monitoring, and detecting client-side JavaScript errors. With this data, developers can fix problems right away, leading to improved website conversion rates and happier customers.