Definition

Interaction to Next Paint (INP) is a web performance metric that measures the time it takes for a web page to respond to user interactions, such as clicks or key presses, and render the next visual update. This metric is crucial for assessing the responsiveness and overall user experience of a website.

Practical Use-Cases

INP is particularly useful for web developers and designers aiming to enhance user experience. By monitoring this metric, teams can identify bottlenecks in their site’s performance and make necessary optimizations. Common scenarios include:

Evaluating the impact of JavaScript execution on responsiveness.
Testing different loading strategies to improve user interaction times.
Assessing the performance of interactive elements like buttons and forms.

Key Aspects

Understanding INP involves recognizing several key aspects:

Measurement: INP is measured from the moment a user interacts with the page until the next visual change occurs.
Thresholds: A good INP score is typically considered to be under 200 milliseconds.
Tools: Various performance monitoring tools, such as Google Lighthouse and WebPageTest, can be used to track INP.

Common Pitfalls and Best Practices

When optimizing for INP, developers should be aware of common pitfalls:

Neglecting to test on real devices can lead to misleading results.
Over-optimizing can sometimes lead to diminishing returns, where further improvements yield minimal benefits.
Failing to account for network conditions can skew INP measurements.

Best practices include regularly testing INP during the development process and making incremental improvements based on user feedback and performance data.

FAQ

What is a good INP score?

A good INP score is generally considered to be under 200 milliseconds, indicating that the page is responsive to user interactions.

How can I improve my INP score?

You can improve your INP score by optimizing JavaScript execution, reducing the size of visual updates, and ensuring that interactive elements load quickly.

What tools can I use to measure INP?

Tools like Google Lighthouse, WebPageTest, and Chrome DevTools are effective for measuring Interaction to Next Paint and other performance metrics.

Why is INP important for user experience?

INP is important because it directly affects how users perceive the responsiveness of a website, influencing their overall satisfaction and likelihood to stay on the site.

Does INP affect SEO?

Yes, INP can indirectly affect SEO as search engines prioritize user experience metrics, and a site with poor responsiveness may rank lower.