INP (Interaction to Next Paint) measures how quickly your UI responds to real user interactions (clicks, taps, key presses) across the whole visit, not just the first one. It replaced FID as the responsiveness Core Web Vital in March 2024 (read more here)
// Key takeaways from the guide
// What INP measures: the latency from user input to the next visual update; the reported value is essentially the slowest interaction observed (ignoring outliers).
// Targets: aim for ≤ 200 ms at p75 (good), 200–500 ms needs improvement, > 500 ms is poor—track mobile and desktop separately.
// How to improve: trim long tasks, optimise event handlers, defer non-critical JS, and reduce main-thread blocking; pair lab checks with field data.
// Why it matters: Better INP = smoother UX and clearer signals for Search. Baseline your key templates, monitor at p75, and set CI guardrails so regressions never reach users.