You’re Probably Using Lighthouse Wrong: How We Got Tricked by a Single Magic Number

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These days web performance is one of the most important things everyone wants to optimize on their apps, and it's clear to everyone how dramatic the impact of a poorly optimized website is on business. Yet we as an industry completely fail in recognizing its complexity and widely misuse the most common tool to measure it — Google Lighthouse. If you’re one of those people thinking that good performance equals a good Lighthouse score, you’ve also fallen into this trap and this talk is for you.

Filip Rakowski
Filip Rakowski
29 min
12 May, 2023

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Video Summary and Transcription

The Talk discusses the importance of performance and mobile consumption in e-commerce, as well as the use and limitations of Google Lighthouse for measuring page quality. It highlights the challenges and considerations in using Lighthouse, including the difference between lab data and real-world data, and the need to understand user experience beyond a single score. The Talk also touches on the potential use of AI in evaluating website performance, optimizing third-party libraries, and setting a JavaScript budget for better performance.

1. Introduction to the Talk

Short description:

Hello. Hey, hey, how are you doing? Are you having fun? I'm happy, because I'm having a lot of fun. It's great to be here again. The title of my talk is, You're Probably Using Cloud House Wrong. My name is Filip Rakovski. I'm a chief developer experience officer and co-founder of Vue. I'm also a technology council member of Maha Alliance. Maha Alliance is an alliance of the biggest enterprise vendors that are modernizing the e-commerce landscape and I'm extremely proud to represent it. I work in the e-commerce industry. Building e-commerce storefront is harder than it seems. And I can guarantee that you will feel physical pain once you learned what faceting is.

Hello. Hey, hey, how are you doing? Are you having fun? Are you having fun? Okay. Good, good. I'm happy, because I'm having a lot of fun.

It's great to be here again. I think it's the first time I'm here in Vue London, in Vue.js Live, this time. And the title of my talk is, You're Probably Using Cloud House Wrong. And I know it sounds a little bit provoking. That was my intention. But I don't assume you're using it wrong. I really hope you're using it in the right way. But just in case you're using it wrong, here's my talk.

My name is Filip Rakovski. I'm a chief developer experience officer and co-founder of Vue. I was introduced as a CTO because I used to be a CTO, but we hired a better CTO. So, right now I can move to the things that I'm best at, and that I enjoy a little bit more. So, yeah. I'm also a technology council member of Maha Alliance. Who here heard about Maha Alliance? Okay. Okay. So, Maha Alliance is an alliance of the biggest enterprise vendors that are modernizing the e-commerce landscape and I'm extremely proud to represent it. And who heard about Vue Storefront? Please raise your hand. Nice. Nice. It's getting better every year.

So, you know, I work in the e-commerce industry. And I work in the e-commerce industry literally all my life. And building e-commerce storefront is harder than it seems. Like if you're powerful after displaying, you know, the first product, the first data on your website from one API endpoint, but the road from there to production is very long and it's often painful. And I can guarantee that you will feel physical pain once you learned what faceting is.

2. Importance of Performance and Mobile Consumption

Short description:

The goal of Vue Storefront is to provide tools that save you from the pain of building e-commerce storefronts. Performance is crucial in the e-commerce industry, and even small delays can cost millions of dollars. Check out WPO stats for insights on how performance optimization can boost revenue. Five years ago, frontend performance was not a significant concern, but with the rise of JavaScript frameworks, the importance of performance became apparent. The growing size of websites and the shift to mobile consumption highlighted the need for better mobile performance.

So, the goal of Vue Storefront is actually to provide tools that save you from this pain. And Vue Storefront is open source, so you can check it on GitHub and give a star if you like it. I'm not encouraging, but, you know, it would be nice.

And in the e-commerce industry, performance is one of the most important things to look at really. The fact that the way how people look at this is often completely wrong is another topic, but that's what I'm going to address in this talk. So, Amazon did a study on that topic. And what they learned is that every 100 milliseconds in added page load costs 1% of revenue. For Amazon, it's millions of dollars, really. 100 milliseconds.

And speaking about numbers, if you need a good source of arguments for your boss, for example, to take care of performance because you know it's important but you need the argument, check out this website, WPO stats, which stands for performance optimization stats. And it will give you great, great insights on how optimizing performance helps other companies to grow their revenue.

And it feels quite crazy from today's perspective, but five years ago, when we were writing the first lines of code for vstorefront, the topic of frontend performance was almost nonexistent in the web developer space. At that time, JavaScript frameworks were just gaining the traction. Angular, JS, React. They were already well-established tools, gaining popularity every day. Vue, it was just getting the attention of the broader developer community, fighting with frameworks like this one.

Do you know those frameworks? Raise your hands if you know all the frameworks, all the logos from this picture. Oh, really? It could have been Vue, but luckily, Vue made it to the third place. So almost no one cared about how fast the website built with those frameworks are. And of course, now everyone say that, you know, putting so much JavaScript on the front end, it was a terrible idea. But honestly, it wasn't that clear at that time. It wasn't that clear because the reason why we are having performance issues with single-page applications these days is because of the ecosystem and how much JavaScript you're adding through the ecosystem, not the frameworks themselves.

And, you know, as long as we're using PCs or laptops as our primary machines, which believe me, like seven years ago was a normal thing to consume the web, no one seemed to be concerned with the growing size of websites. Both CPU and internet bandwidth, they were growing faster and websites were growing in their size. It all changed when mobile phones started to become the preferred way of consuming the web. And according to Google Research in 2017, into it's took on average 15 seconds to fully load a webpage on a mobile phone. Imagine 15 seconds. If I wouldn't have only 20 minutes, I would just wait to give you, you know, this perception. At that time, the awareness about the impact of this poor mobile performance on their business started to emerge. But we're still lacking an easy way to actually link those two components.

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