What Impact Do Web Fonts and Images Have on Interaction to Next Paint (INP), and How Can I Optimize Them to Improve This Core Web Vitals Metric?


Web fonts and images significantly impact the Interaction to Next Paint (INP) metric. Optimizing these elements involves using efficient loading strategies, compressing files, and serving responsive images and fonts. Here’s a detailed guide on how to enhance INP by optimizing web fonts and images.

Understanding INP and Its Importance

Interaction to Next Paint (INP) measures the time from when a user interacts with a page (like clicks or taps) to the next time the browser displays something new after responding to that interaction. An optimized INP ensures users experience smooth and responsive interactions.

Impact of Web Fonts on INP

Web fonts can affect INP due to the loading time required before text becomes visible. Poorly optimized web fonts may result in delayed content rendering, leading to a slower response time.

Strategies to Optimize Web Fonts

Preloading Fonts

Use `` to load fonts earlier. This strategy helps reduce the delay before text rendering, improving INP [Preload Critical Assets, 2022].

Font Display Property

Implement the `font-display: swap` property to ensure fallback fonts are displayed immediately, reducing invisible text time [Web Font Optimization, 2023].

Subsetting Fonts

Load only the required character sets by subsetting fonts. This reduces file size and loading time [Web Font Best Practices, 2022].

Impact of Images on INP

Images can impact INP by delaying the rendering of new content when user interaction causes images to load. Optimizing image delivery can significantly enhance this metric.

Strategies to Optimize Images

Responsive Images

Use the `

` tag’s `srcset` and `sizes` attributes to serve images appropriate for the user’s screen size. This can reduce unnecessary image loading time [Serve Responsive Images, 2023].

Image Compression

Apply image compression techniques using formats like WebP, JPEG XR, and AVIF. These formats offer better compression ratios, reducing load times [Use Imagemin to Compress Images, 2022].

Lazy Loading

Implement lazy loading for non-critical images to defer their loading until necessary. This practice helps prioritize content rendering that responds to user interaction [Lazy Loading, 2023].

Additional Optimization Techniques

Caching and CDN Usage

Using Content Delivery Networks (CDNs) and caching strategies can reduce latency by serving fonts and images from servers closer to the user. This method boosts loading efficiency and speeds up interaction responses [Use a CDN, 2023].

Minimizing Critical Rendering Path

Minimize the critical rendering path by inlining critical CSS and JavaScript, reducing render-blocking resources. This approach ensures faster render times for interactive elements [Understanding the Critical Rendering Path, 2023].


Optimizing web fonts and images is crucial for enhancing the Interaction to Next Paint (INP) metric. Implementing strategies such as preloading fonts, using the font-display property, compressing images, and leveraging responsive design can significantly improve INP, resulting in a smoother user experience.