Best practices for modern frontend monitoring

Single-page applications (SPAs) offer benefits such as flexibility in moving application logic to the frontend and a smooth user experience with fewer page loads. However, monitoring end-user experiences is crucial for ensuring that SPAs run smoothly on all devices. Traditional methods of frontend performance monitoring are not sufficient for SPAs, which require tracking dynamic page elements like animations, API calls, and rendering lifecycles. A user-centric approach to frontend monitoring involves listening to browser events and tracking user interactions over time. Three aspects of single-page apps that can help optimize users' experience include route changes, user interactions, and errors. Monitoring these aspects requires a combination of techniques such as tracking Largest Contentful Paint (LCP), using User Timing API, listening to route changes, and implementing error tracking.