How to Reduce LCP on Mobile for Your Shopify Store Using the Dawn Theme

By Tony Ng.
June 21st, 2024

How to Reduce LCP on Mobile for Your Shopify Store Using the Dawn Theme

Introduction

Good evening, Shopify enthusiasts! If you've been struggling with reducing your Largest Contentful Paint (LCP) on mobile for your Shopify store using the Dawn theme, you're not alone. Having optimized images and still not seeing improvements can be frustrating. Understanding how to optimize your code further with defer or async can be the key to unlocking better performance. This post will provide you with a detailed, step-by-step guide to help you achieve a reduced LCP, potentially leading to passing Core Web Vitals, which is crucial for both user experience and SEO.

What is LCP and Why Does It Matter?

LCP, or Largest Contentful Paint, measures the time it takes for the largest content element in the viewport to become visible. For mobile users, this is a crucial metric since slower load times can lead to higher bounce rates. Core Web Vitals, including LCP, are considered a ranking factor by search engines, meaning a high LCP can negatively impact your SEO.

Common Causes of High LCP on Mobile

Before diving into the solution, it's important to identify common issues that lead to high LCP:

Unoptimized Images: Large, uncompressed images can significantly slow down page load times.
Render-Blocking JavaScript and CSS: Scripts that block the rendering of your page make users wait longer to see the content.
Slow Server Response Times: A server that takes too long to respond will delay the loading of your largest contentful element.
Client-Side Rendering: Heavy reliance on client-side rendering can delay the visibility of key elements.

Step-by-Step Guide to Reducing LCP on Mobile Using the Dawn Theme

1. Optimize Your Images

You've mentioned that you've already optimized your images, but it's always good to double-check:

Use responsive image tags (<img srcset> and <picture> elements) to serve different image sizes for different screen sizes.
Compress images using tools like TinyPNG or built-in Shopify features.
Serve images in modern formats like WebP which are smaller and load faster.

2. Minimize Render-Blocking Resources

JavaScript and CSS that block rendering can significantly increase LCP times. Here’s how to handle these resources:

Defer and Async JavaScript

To defer non-critical JavaScript, add the defer attribute to <script> tags:

<script src="path-to-your-script.js" defer></script>

Alternatively, for scripts that can load asynchronously, use the async attribute:

<script src="path-to-your-script.js" async></script>

Split Critical and Non-Critical CSS

Move critical CSS directly into your HTML document's <head> section and load non-critical CSS asynchronously:

<link rel="stylesheet" href="non-critical.css" media="print" onload="this.media='all'">
<noscript><link rel="stylesheet" href="non-critical.css"></noscript>

3. Leverage Browser Caching and Server Optimization

Caching can significantly improve page load times:

Configure browser caching in your server settings.
Use Content Delivery Networks (CDNs) to reduce server load and improve response times.

4. Reduce Client-Side Rendering

If your Dawn theme uses a lot of client-side rendering, consider moving some of it to the server side. While this may require more advanced technical skills, it's an effective way to reduce LCP.

Dealing with Specific Issues

Since the Dawn theme is well-optimized, you could be dealing with something specific to your store. Share your URL in forums or consult a professional (being cautious of scammers), as they can often provide advice tailored to your unique situation.

Questions and Answers

Q1: Is it possible to implement these changes without hiring a developer?

A1: Yes, many of these changes can be implemented without hiring a developer, especially if you're comfortable working with HTML and CSS. However, for more advanced optimizations like server-side rendering, consulting with a professional may be beneficial.

Q2: Can reducing LCP improve my SEO rankings?

A2: Absolutely. LCP is a part of Google's Core Web Vitals, which are used as a ranking factor. Improving your LCP can lead to better search engine rankings and more organic traffic.

Conclusion

Reducing LCP on mobile for your Shopify store using the Dawn theme involves a mix of optimizing images, minimizing render-blocking resources, leveraging caching, and potentially reducing client-side rendering. By following the steps outlined in this guide, you should be well on your way to improving your Core Web Vitals and enhancing both user experience and SEO. Remember, if you're stuck, consider sharing your URL for specific advice or consult with a professional—just be cautious of potential scammers.

Good luck, and happy optimizing!