Interaction to Next Paint (INP) is the 2024 Core Web Vital that replaced FID. Aggregate INP tells you the page is slow; this tool attributes each slow interaction to the specific event handler + script origin. Load a URL in the iframe, click around, and watch the attribution table fill in.
Read the story behind this tool: INP Attribution — Which Click Actually Broke The 200ms Budget →
The page loads in a sandboxed iframe. INP is measured on interactions inside the frame. Click around naturally — open menus, fill inputs, select options. The profiler records every interaction longer than 50 ms.
Note: cross-origin pages may block the PerformanceObserver bridge. For most reliable results, deploy this tool on the same origin as the target page (or run against your own domain).