Web Performance Monitoring That Actually Matters
Most performance dashboards track too much. Focus on these metrics and you'll catch 90% of user-impacting issues.
Measure What Users Feel
Performance monitoring is easy to overcomplicate. Teams install comprehensive observability stacks, track hundreds of metrics, and build dashboards that nobody checks. Meanwhile, users are experiencing slow page loads and unresponsive interactions that go undetected because they're buried in noise.
The metrics that matter are the ones that correlate with user experience. Google's Core Web Vitals framework provides a useful starting point because it measures what users actually perceive: loading speed, interactivity, and visual stability.
The Essential Metrics
Largest Contentful Paint (LCP). How long before the main content is visible? Target: under 2.5 seconds. This is the metric that most closely correlates with perceived load speed. When users say "your site is slow," they're usually describing a poor LCP.
Interaction to Next Paint (INP). How responsive is the page to user input? Target: under 200ms. A page can load quickly but still feel sluggish if clicks and taps take too long to respond. INP captures this responsiveness across the entire page lifecycle.
Error rates by endpoint. Track the percentage of API calls that return errors, grouped by endpoint. A 2% error rate on your checkout endpoint is a revenue emergency. A 2% error rate on your "about us" page is a low-priority fix. Context determines urgency.
