First Contentful Paint (FCP) is a performance metric that measures the time it takes from when a user starts loading a webpage to when they see the first visual content on the screen. It’s one of the key metrics that indicates how quickly a user perceives that a page is loading. Optimizing for FCP can result in a better user experience.
Here are steps to optimize for FCP:
- Critical Rendering Path (CRP) Optimization:
- Minimize the number of critical resources: Reduce the number of resources marked as
critical. - Minimize the critical depth: Optimize the order in which the remaining critical resources are loaded. Resources should be loaded in the order they’re used.
- Minimize the critical bytes: Optimize the number of bytes downloaded for critical resources.
- Minimize the number of critical resources: Reduce the number of resources marked as
- Optimize CSS:
- Inline critical CSS: This means taking the styles required to render the above-the-fold content and placing it directly in the HTML.
- Use
mediaattributes for non-critical CSS: E.g.,<link rel="stylesheet" href="style.css" media="print">for print styles. - Remove unused CSS or use tools like PurgeCSS to automatically remove unused styles.
- Minify and compress CSS files.
- Optimize JavaScript:
- Defer non-critical JavaScript: Using the
deferattribute on scripts allows them to be parsed and executed after the HTML is parsed. - Minify and compress JavaScript files.
- Remove any unused JavaScript or use tree shaking with modern bundlers like Webpack.
- Defer non-critical JavaScript: Using the
- Optimize Fonts:
- Use
font-display: optionalorfont-display: swapin your@font-facerule to ensure text remains visible during webfont loads. - Serve fonts in WOFF2 format for modern browsers because it offers better compression than other formats.
- Host fonts locally rather than relying on external font providers which might slow down FCP.
- Preload key fonts using
<link rel="preload" href="font.woff2" as="font" type="font/woff2" crossorigin>
- Use
- Optimize Images:
- Lazy-load offscreen images using the
loading="lazy"attribute onimgtags. - Serve images in modern formats like WebP which provide better compression.
- Use responsive images with
srcsetandsizesattributes. - Compress images without losing quality.
- Lazy-load offscreen images using the
- Server and CDN:
- Use HTTP/2 or HTTP/3, which allow for faster parallel resource downloading.
- Use a Content Delivery Network (CDN) to serve assets from a location closest to the user.
- Implement server compression with Gzip or Brotli.
- Preconnect and Preload:
- Use
<link rel="preconnect">for key third-party origins. - Preload critical assets using
<link rel="preload">.
- Use
- Remove Render-blocking Resources:
- Check for any scripts or stylesheets that block rendering and either defer, async, or inline them based on their criticality.
- Other:
- Optimize third-party scripts as they can have a significant impact on performance.
- Consider using a Progressive Web App (PWA) shell to instantly load content on repeat visits.
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Here are some tips to optimize for FCP and where to place important details:
- Minimize Render-Blocking Resources:
- Reduce the number of external CSS and JavaScript files that block rendering. Inline critical CSS and load non-critical resources asynchronously.
- Consider using asynchronous and deferred loading for JavaScript files, so they don’t block the rendering process.
- Optimize Images:
- Compress and serve images in modern formats like WebP.
- Specify image dimensions in HTML to prevent layout shifts.
- Use responsive images with
srcsetandsizesattributes to load appropriate sizes for different screen resolutions.
- Prioritize Above-the-Fold Content:
- Identify and prioritize the content that’s visible without scrolling (above-the-fold). Make sure this content loads quickly.
- Inline critical styles and scripts to ensure the initial rendering is as fast as possible.
- Lazy Loading:
- Implement lazy loading for images that are initially off-screen. This reduces the initial load time by only loading images when they are about to come into the user’s view.
- Minimize Server Response Time:
- Optimize server-side code to reduce the time it takes to generate and deliver the initial HTML response.
- CDN Usage:
- Utilize a Content Delivery Network (CDN) to serve your assets from geographically distributed servers, reducing latency and improving load times.
- Reduce Third-Party Dependencies:
- Minimize the number of third-party scripts and resources, as they can add significant overhead to page loading.
- Asynchronous Loading:
- Use the
asyncattribute for non-essential scripts to prevent them from blocking the main rendering process.
- Use the
- Critical Rendering Path:
- Optimize the critical rendering path to minimize the time it takes for the browser to render the page.
- Minimize the use of complex CSS selectors and styles that could slow down rendering.
- Progressive Rendering:
- Break your page into smaller sections that can be rendered progressively, giving users a sense of fast loading even if the entire page is not yet fully loaded.
- Cache and Prefetch:
- Implement appropriate caching mechanisms for static assets to reduce subsequent loading times.
- Use
prefetchandpreloadhints to let the browser know which resources to load early.
- Use a Performance Monitoring Tool:
- Utilize tools like Google PageSpeed Insights, Lighthouse, or WebPageTest to analyze your page’s performance and identify areas for improvement.
Regarding where to place details:
- Place critical assets in the head: Essential styles and scripts (after being minimized) can be placed in the
<head>to ensure they are loaded and applied as soon as possible. But remember, scripts should be deferred if they’re not essential for initial rendering. - Place non-critical assets before the end of the body: To avoid render-blocking, non-critical scripts and sometimes even non-critical styles can be placed just before the closing
</body>tag. - Asynchronously load non-essential content: For components or details that aren’t immediately necessary for the user (e.g., below-the-fold content, additional widgets, etc.), load them asynchronously after the main content.
Remember that optimizing for FCP is part of the larger picture of web performance. Always test your optimizations using tools like Lighthouse, and WebPageTest, and monitor real-user metrics to ensure that changes are having the desired impact.
Optimizing for FCP usually involves focusing on critical rendering path optimization. Here are some PHP-related techniques and where you’d typically implement them:
- Reduce Server Response Times:
- Code Level: Optimize your PHP application to respond faster. This could involve optimizing database queries, using caching solutions like Memcached or Redis, and ensuring efficient code.
- Configuration Level: Configure your server for speed. If you’re using Apache, consider switching to Nginx or using a solution like LiteSpeed. Alternatively, you could optimize Apache with mod_pagespeed.
- Optimize Critical CSS:
- Use tools to extract and inline “critical” CSS. This means only the CSS needed to render the above-the-fold content. There are several online tools and node packages like
criticalthat can help with this. - Code Level: Inline the critical CSS directly in the
<head>of your PHP templates, and load non-critical CSS asynchronously.
- Use tools to extract and inline “critical” CSS. This means only the CSS needed to render the above-the-fold content. There are several online tools and node packages like
- Load Fonts Asynchronously:
- Code Level: If your PHP templates specify web fonts, ensure they don’t block rendering. Use
font-display: swap;in your CSS to ensure text remains visible during webfont loads.
- Code Level: If your PHP templates specify web fonts, ensure they don’t block rendering. Use
- Defer Non-Critical JavaScript:
- Code Level: In your PHP templates, move non-critical JS scripts to the bottom of the page or use the
deferattribute to ensure they don’t block the rendering of your page.
- Code Level: In your PHP templates, move non-critical JS scripts to the bottom of the page or use the
- Optimize Images:
- Code Level: If your PHP code is responsible for serving images, ensure they’re appropriately sized and compressed. Libraries like
ImageMagickor tools likejpegoptimandoptipngcan be utilized server-side to help with this. - Configuration Level: Leverage browser caching for images. This often involves server configuration, ensuring that Cache-Control headers are set for static assets.
- Code Level: If your PHP code is responsible for serving images, ensure they’re appropriately sized and compressed. Libraries like
- Leverage Browser Caching:
- Configuration Level: Ensure that static assets like CSS, JS, and images have appropriate Cache-Control headers set. This is typically done in
.htaccessfor Apache or in server blocks for Nginx.
- Configuration Level: Ensure that static assets like CSS, JS, and images have appropriate Cache-Control headers set. This is typically done in
- Enable Compression:
- Configuration Level: Use Gzip or Brotli compression on the server. This reduces the size of the transmitted data.
- Code Level: If you have custom mechanisms for serving content, ensure they’re sending compressed data for supported clients.
- Implement a Content Delivery Network (CDN):
- Not exactly PHP-specific, but CDNs can significantly improve FCP for users that are geographically distant from your server. Integrate a CDN to serve your website’s static assets.
Place of Implementation:
- For optimizations directly affecting the HTML output (like inlining critical CSS), you’d implement them in your PHP templates or views.
- For server configurations (like enabling compression or browser caching), they’d typically go into your server’s config files, such as Apache’s
.htaccessor Nginx’s server blocks.
Lastly, always monitor the impact of your optimizations using tools like Google’s PageSpeed Insights, Lighthouse, or WebPageTest. This helps you understand the effect of your changes on FCP and other performance metrics.
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