Lazy loading for SEO

Vasiliy Pupkin Tetiana

Due to the slow loading of the page, many companies lose potential customers. It is believed that if it takes more than 3 seconds to reload a page on your site, lazy loading of content is exactly what can help and speed up page loading.

Next, let's look at what lazy loading is, how to set it up, and how it affects SEO promotion.

What is lazy loading

Let's imagine, you are creating a website, which itself is a set of completely different files — html, php, css, js, images, videos, etc. If there are a lot of these elements on the site or they are large — all of them can slow down your site. Since large files, especially images and videos, take a long time to load.

When visitors open a page on the site, its content begins to load. This allows the browser to cache all the information, but this does not mean that all users will be able to see all the content that is located on the page.

If data takes a long time to load, it does not mean that all users will wait for this. At the time of information technology, people are already accustomed to quickly receiving information or leaving quickly in search of a resource that will give them the necessary information faster. The first requirement of modern web resources — is fast loading website.

You can expect users to wait until the end of the page to load, but in fact, they can look at the first screen and how slowly it loads, and leave. This means you've wasted memory and bandwidth by loading the bottom half of the page, which they never scroll to.

With lazy loading, your site loads gradually as the user navigates down the page. With this setting, only the top part of the page is loaded on the page, and the bottom part of it will contain a "stub".

When the user scrolls down the page, the content under the "stub" is gradually loaded and replaced with the actual content. With lazy loading, you don't load all of the page's content at once. It is loaded when users scroll the page.

Lazy loading is an alternative to bulk loading all your content. Instead of waiting for your entire site to load, your audience can quickly access information. Your page only loads when needed.

When you have a site that takes too long to load, you get a higher bounce rate, and a high bounce rate impacts your SEO in a bad way. Read more about web analytics in our another article — Google Universal Analytics vs Google Analytics 4.

lazy loading for seo

How lazy loading affects SEO

From the above, it may seem that lazy loading is the solution to all problems since the page loads quickly and does not waste extra resources. However, there are some things to consider when it comes to SEO optimization.

Lazy loading affects how search engines crawl your site. If your page doesn't load right away, search engines can't crawl the entire page. This threatens that your content will be ignored or misinterpreted.

Unlikely will you agree that search engines receive incomplete information about your site, because this negatively affects the ranking of the resource in the search results. On the other hand, this does not mean that you cannot use lazy loading. If you are using lazy loading you need to make sure that all relevant content is visible in the viewport. This can be implemented with the help of IntersectionObserver API and polyfill. This ensures that Google bots see all of your content when they crawl your site.

You should make sure that the pages of your site support pagination even when you implement infinite scrolling. With pagination, search engines can crawl all the pages of the site to the end, and users can share your content.

Lazy loading recommendations from Google

To help companies adapt sites for lazy loading, Google has created a document according to which webmasters can set up sites to crawl correctly when using lazy loading. 

In this document, Google recommends to provide content loading in the viewport. The document also highlights the need to provide unique links to content that does not load immediately.

In short, when working with lazy loading, Google recommends following these rules:

  1. Make sure all content on your page is accessible by Googlebot.
  2. Check to see if all the content you want is loading as it appears in the viewport.
  3. Provide pagination support for infinite scrolling.
  4. Check out how lazy loading works with the Puppeteer script.

Benefits of using lazy loading for SEO

1. It speeds up the loading of website pages

Lazy loading is the sweet spot between quick access to information for users and saving page loading resources. When using this technology, users get the information they came to your site for faster. And the site itself, meanwhile, will load the rest of it, which is below the first screen.

2. It keeps users on the site longer

Nowadays the speed of access to information is a very important factor. If a visitor on your site received information quickly and did not go back to the search results due to the slow loading of the page, he will stay with you even longer. Fast sites now are popular and trustworthy.

3. Helps Maximize Resources

Since the site does not load the page completely, but does it gradually, as it scrolls, it does not waste extra resources, shows the response faster, and helps save bandwidth if the user is not going to look at the site beyond the first screen. Thus, more users will be able to access your information in a shorter time.

Basic rules for efficient use of lazy Loading

Lazy loading can be very effective for SEO. However, in order to achieve the maximum effect, you should follow several recommendations.

Use lazy loading only for content below the first screen

Lazy loading is only effective when used for the bottom of the page. If you integrate the technology at the very beginning of the page, then the whole page will load more slowly.

Place useful content or part of it on the first screen of the site

In order to interest the user, it is worth placing a piece of useful information at the beginning of the page. This may be a partial answer to his request, or an introduction to a more complete answer. Thus, the user will be interested in your page and will be ready to read the rest of the content searching for a complete answer.

Optimize videos and images on the page

Pictures and videos have the biggest impact on your page loading speed. These files are usually larger than all others. If you want to speed up page loading, in addition to lazy loading, you also need to optimize the largest files on the page.

To optimize and compress images, you can use the tiny png service. When it comes to optimizing your videos, it's best to host them on an external site like YouTube. Such videos can then be embedded in the content of the page and they will not use its additional resources, slowing down the display of content.

tiny png to compress images


Lazy loading can help reduce the loading time of your site. Instead of waiting for pages to load fully, you can quickly serve content to your audience. For the technology to work more efficiently, it is enough to set it up correctly and follow the simple recommendations of the Google search engine. Optimize the content on the first screen and optimize the largest files on the page.

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