Web Performance Glossary

Core Web Vitals

What is INP?

Interaction to Next Paint measures how long the page takes to respond visually after a visitor clicks, taps, or types. It replaced First Input Delay as the Core Web Vitals responsiveness metric.

Plain-English version

How quickly the page responds to taps and clicks.

Target

Under 200ms

INP thresholds

Use thresholds as a triage tool. Field data matters most when there is enough real Chrome traffic for the page.

Good

≤ 200ms

Needs work

200–500ms

Poor

> 500ms

Why it matters

What a visitor feels when INP is bad.

Why INP matters

INP is what makes a site feel responsive or stuck. Slow interactions are especially painful on mobile, checkout pages, filters, menus, and forms.

What a poor result usually means

A poor INP usually means JavaScript is keeping the main thread busy, third-party scripts are doing too much work, event handlers are expensive, or rendering after an interaction is heavy.

What to fix first

Do not chase the score. Fix the bottleneck.

The right fix depends on the metric, the page template, and whether the issue appears in real visitor data.

  1. Find the slowest interactions, not just the largest JavaScript files.
  2. Break up long tasks and defer non-critical JavaScript.
  3. Reduce third-party script work during interaction-heavy moments.
  4. Move expensive work off the main thread where possible.
  5. Simplify components that re-render too much after clicks or typing.

How nimo helps

Ask nimo: “Why is my INP high and how can I improve responsiveness?

nimo connects responsiveness warnings to real visitor data and helps separate one noisy script from the interaction that users actually feel.

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