Measures input responsiveness — the delay between user interaction and the next visual update.
Interaction to Next Paint (INP) is a Core Web Vital that measures how quickly your page responds to user interactions like clicks, taps, and key presses. It captures the full latency from when a user interacts with the page to when the browser paints the next frame reflecting that interaction. A good INP is 200ms or less.
INP replaced First Input Delay (FID) as the official Core Web Vital for responsiveness in March 2024. Unlike FID, which only measured the first interaction, INP measures the worst interaction throughout the entire page lifecycle. This gives a much more accurate picture of how responsive your page actually feels to users.
Poor INP (above 500ms) directly affects your Core Web Vitals assessment in Google Search Console and can negatively impact search rankings. Users perceive sluggish pages as broken or low-quality, leading to higher bounce rates and lower engagement.
// Measure INP using PerformanceObserver
new PerformanceObserver((list) => {
for (const entry of list.getEntries()) {
console.log('INP candidate:', entry.duration);
}
}).observe({ type: 'event', buffered: true, durationThreshold: 16 });Run a free audit to see how your site performs on Interaction to Next Paint (INP) and 159 other checks.
Start Free AuditChecks if images use responsive techniques like srcset.
Checks if images have width and height attributes to prevent layout shift.
Checks for JavaScript errors in the browser console. (Note: In-dev check)
Measures the total size of the HTML document.