What is lazy loading?

The majority of online traffic is generated with mobile devices, where loading time matters a lot. User experience, conversion rates, SEO performance & general quality of the website are direct derivatives of it as well. If You’ve put some time on researching the topic of website loading times, You’ve probably come across the lazy loading term.
One of the most important things when managing a website is to make sure it works well. Aside from the emphasis on getting it right, it’s also about time – something that is as desirable as money these days. People have less and less patience, which leads to faster irritation with slow-loading websites.

What is lazy loading in digital marketing?

Lazy loading – also known as on-demanding loading or asynchronous loading. It is all about spreading the loading of certain items on the page over time. The most important content can load faster and earlier than less important items. In the final result, the text content will load first, but pictures, graphical elements & videos will be delayed or loaded after a scroll – the user’s browser will be waiting until the additional resources are needed.

Lazy loading can boost overall performance of Your website

Making sure that Your website is optimized for modern user behavior and the devices used by them (mostly mobile) may be one of the most important aspects of website optimization. According to online research, if the page loading times deteriorate, the conversion rate drops. Every second of delay decreases the CR to up to 20%. Google states that bounce rate is also affected negatively when the website is slow. The research is not new, but it is reasonable to say that this effect is even more important now, than just a few years ago.

Lazy loading is one of the most important improvements You can introduce to the overall optimization of the website loading times. This has a very positive effect on the experience of using websites. Infinite scroll, which is used together with lazy loading, causes the content to load relative to the page scrolling down. Lazy load also minimizes the network load. On-demand data transfer significantly reduces the amount of that data at one time, thus saving transfer.

The importance of lazy loading in SEO

SEO performance depends on the website speed in general. The most common validators of the loading times are referred to as Core Web Vitals, a set of parameters that measure important stages of the website loading process.

Core Web Vitals are gaining more and more importance in Google’s algorithm that ranks websites. Those parameters are influencing the positions in SERP, so there is a necessity to optimize them.

Lazyload is one of the simplest ways of improving the speed of websites and quite effective as well. You need to remember that implementation of this mechanism should be delivered globally, for every URL, every page. Google is evaluating the performance of Your website in the same manner, not only the homepage.

Lazy load – verification & implementation

Surely, it is worth checking if this mechanism is implemented & if so, what is its status. Boostsite is able to analyze lazy load on every URL with verification, if it functions properly or not. Just in case Your website does not have this feature, please refer to the implementation instructions below.

Lazy load implementation on WordPress

WordPress CMS makes lazy load implementation relatively simple. There are a number of free & paid plugins that support this solution. The list is long, but here are the most popular in 2022:

• Lazy Load by WP Rocket
• A3 Lazy Load
• Autoptimize
• W3 Total Cache

Some of the plugins are dedicated to lazy load optimization, but there are solutions that provide this along with other useful features that can help optimizing Your WordPress.

Simple way of implementing lazy loading

Not all of the websites are created using customizable Content Management Systems, but there are ways to introduce lazy loading feature to all of them. If You are unable to implement lazy loading on your website Yourself, You need to ask Your programmer to insert the script into the code. You will also find a lot of open source libraries online, that will contain the lazy loading function:
yall.js – lightweight library
lazysizes – a library that positively influences positioning and provides a few additional plugins with other functions
lazyload – script that loads images automatically when the user views them
blazy.js – lightweight JS library useful when loading iframes or images

Co-author: Alicja Moczko

Tomasz Więckowski

15+ years of experience in effective business & marketing management, often in both corporate & startup environments. Effective marketing manager & a digital marketing expert. Business-oriented, with proven skills to scale up sales & revenues with consideration of CAC vs LTV customer lifecycle management, product development & ROI / ROAS optimization.