Earlier this year, Google announced that Interaction to Next Paint (INP) is no longer an experimental metric. INP will replace First Input Delay (FID) as a Core Web Vital in March of 2024.
Now that INP has arrived to dethrone FID as the responsiveness metric in Core Web Vitals, we've turned our eye to scrutinizing its effectiveness. In this post, we'll look at real-world data and attempt to answer: What correlation – if any – does INP have with actual user behavior and business metrics?
This month, SpeedCurve enters double digits with our tenth birthday. We're officially in our tweens! (Cue the mood swings?)
I joined the team in early 2017, and I'm blown away at how quickly the years have flown by. Every day, I marvel at my great luck in getting to work alongside an amazing team to build amazing tools to help amazing people like you!
In the spirit of celebration, I thought it would be fun to round up my ten favourite things to do in SpeedCurve (that I think you'll like, too). Keep scrolling to learn how to:
As we all know, naming things is hard.
Google's Core Web Vitals are an attempt to help folks new to web performance focus on three key metrics. Not all of these metrics are easy to understand based on their names alone:
Any time a new metric is introduced, it puts the burden on the rest of us to first unpack all the acronyms, and then explore and digest what concepts the words might refer to. This gets even trickier if the acronym stays the same, but the logic and algorithm behind the acronym changes.
In this post, we will dive deeper into Cumulative Layout Shift (CLS) and how it has quietly evolved over the years. Because CLS has been around for a while, you may already have some idea of what it represents. Before we go any further, I have a simple question for you:
How do you think Cumulative Layout Shift is measured?
Hold your answer in your head as we explore the depths of CLS. I'm interested if your assumptions were correct, and there's a poll at the bottom of this post I'd love you to answer.
Demonstrating the impact of performance on your users – and on your business – is one of the best ways to get your company to care about the speed of your site.
Tracking goal-based metrics like conversion rate alongside performance data can give you richer and more compelling insights into how the performance of your site affects your users. This concept is not new by any means. In 2010, the Performance and Reliability team I was fortunate enough to lead at Walmartlabs shared our findings around the impact of front-end times on conversion rates. (This study and a number of other case studies tracked over the years can be found at WPOstats.)
Setting up conversion tracking in SpeedCurve RUM is fairly simple and definitely worthwhile. This post covers:
For more than ten years, I've been writing about page bloat, its impact on site speed, and ultimately how it affects your users and your business. You might think that this topic would be played out by now, but every year I learn new things – beyond the overarching fact that pages keep getting bigger and more complex, as you can see in this chart, using data from the HTTP Archive.
In this post, we'll cover:
Today at Google I/O 2023, it was announced that Interaction to Next Paint (INP) is no longer an experimental metric. INP will replace First Input Delay (FID) as a Core Web Vital in March of 2024.
It's been three years since the Core Web Vitals initiative was kicked off in May 2020. In that time, we've seen people's interest in performance dramatically increase, especially in the world of SEO. It's been hugely helpful to have a simple set of three metrics – focused on loading, interactivity, and responsiveness – that everyone can understand and focus on.
During this time, SpeedCurve has stayed objective when looking at the CWV metrics. When it comes to new performance metrics, it's easy to jump on hype-fuelled bandwagons. While we definitely get excited about emerging metrics, we also approach each new metric with an analytical eye. For example, back in November 2020, we took a closer look at one of the Core Web Vitals, First Input Delay, and found that it was sort of 'meh' overall when it came to meaningfully correlating with actual user behavior.
Now that INP has arrived to dethrone FID as the responsiveness metric for Core Web Vitals, we've turned our eye to scrutinizing its effectiveness.
In this post, we'll take a closer look and attempt to answer:
It's easier to make a fast website than it is to keep a website fast. If you've invested countless hours in speeding up your pages, but you're not using performance budgets to prevent regressions, you could be at risk of wasting all your efforts.
In this post we'll cover how to:
This bottom of this post also contains a collection of case studies from companies that are using performance budgets to stay fast.
Let's get started!
There is a lot of excitement in the world of web performance these days, and April has been no exception! At SpeedCurve, we've been focused on staying on top of the items that affect you the most.
Here is a look at what's new in SpeedCurve:
All of this work driven by the community is having a big impact in our collective goal to make performance accessible for everyone.
Read on to learn more about these exciting changes!
"I made my pages faster, but my business and user engagement metrics didn't change. WHY???"
"How do I know how fast my pages should be?"
"How can I demonstrate the business value of performance to people in my organization?"
If you've ever asked yourself any of these questions, then you could find the answers in identifying and understanding the performance plateau for your site.
The performance plateau is the point at which changes to your website’s rendering metrics (such as Start Render and Largest Contentful Paint) cease to matter because you’ve bottomed out in terms of business and user engagement metrics.
In other words, if your performance metrics are on the performance plateau, making them a couple of seconds faster probably won't help your business.
The concept of the performance plateau isn't new. I first encountered it more than ten years ago, when I was looking at data for a number of sites and noticed that – not only was there a correlation between performance metrics and business/engagement metrics – there was also a noticeable plateau in almost every correlation chart I looked at.
A few months ago someone asked me if I've done any recent investigation into the performance plateau, to see if the concept still holds true. When I realized how much time has passed since my initial research, I thought it would be fun to take a fresh look.
In this post, I'll show how to use your own data to find the plateau for your site, and then what to do with your new insights.
One of the great things about Google's Core Web Vitals is that they provide a standard way to measure our visitors’ experience. Core Web Vitals can answer questions like:
Sensible defaults, such as Core Web Vitals, are a good start, but one pitfall of standard measures is that they can miss what’s actually most important.
Largest Contentful Paint (LCP) makes the assumption that the largest visible element is the most important content from the visitors’ perspective; however, we don’t have a choice about which element it measures. LCP may not be measuring the most appropriate – or even the same – element for each page view.
In the case of a first-time visitor, the largest element might be a consent banner. On subsequent visits to the same page, the largest element might be an image for a product or a photo that illustrates a news story.
The screenshots from What Hifi (a UK audio-visual magazine) illustrate this problem. When the consent banner is shown, then one of its paragraphs is the LCP element. When the consent banner is not shown, an article title becomes the LCP element. In other words, the LCP timestamp varies depending on which of these two experiences the visitor had!
What Hi Fi with and without the consent banner visible
It's been another busy month here at SpeedCurve! Check out our latest product updates below.
We've been busy here at SpeedCurve HQ! Here's a roundup of our recent product updates.
Experimentation tools that use asynchronous scripts – such as Google Optimize, Adobe Target, and Visual Web Optimizer – recommend using an anti-flicker snippet to hide the page until they've finished executing. But this practice comes with some performance measurement pitfalls:
In this post we'll look at how anti-flicker snippets work, their impact on Web Vitals, and how to measure the delay they add to visitors' experience.
Page Speed Benchmarks is an interactive dashboard that lets you explore and compare web performance data for leading websites across several industries – from retail to media – over the past year. This dashboard is publicly available (meaning you don't need a SpeedCurve account to explore it) and is a treasure trove of meaningful data that you can use for your own research.
The dashboard allows you to easily filter by region, industry, mobile/desktop, fast/slow, and key web performance metrics, including Google's Core Web Vitals. (Scroll down to the bottom of this post for more testing details.)
At the time of writing this post, these were the home pages with the fastest Start Render times in key industries:
As you can see, I've included Largest Contentful Paint alongside Start Render in this chart, for reasons I explain below.
(See our more recent page growth post: What is page bloat? And how is it hurting your business, search rank, and users?)
I've been writing about page size and complexity for years. If you've been working in the performance space for a while and you hear me start to talk about page growth, I'd forgive you if you started running away. ;)
But pages keep getting bigger and more complex year over year – and this increasing size and complexity is not fully mitigated by faster devices and networks, or by our hard-working browsers. Clearly we need to keep talking about it. We need to understand how ever-growing pages work against us. And we need to have strategies in place to understand and manage our pages.
In this post, we'll cover:
Chances are, you're here because of Google's update to its search algorithm, which affects both desktop and mobile, and which includes Core Web Vitals as a ranking factor. You may also be here because you've heard about the most recent potential candidates for addition to Core Web Vitals, which were just announced at Chrome Dev Summit.
A few things are clear:
If you're new to Core Web Vitals, this is a Google initiative that was launched in early 2020. Web Vitals is (currently) a set of three metrics – Largest Contentful Paint, First Input Delay, and Cumulative Layout Shift – that are intended to measure the loading, interactivity, and visual stability of a page.
When Google talks, people listen. I talk with a lot of companies and I can attest that, since Web Vitals were announced, they've shot to the top of many people's list of things to care about. But Google's prioritization of page speed in search ranking isn't new, even for mobile. As far back as 2013, Google announced that pages that load slowly on mobile devices would be penalized in mobile search.
Keep reading to find out:
Phew! Between the fast-paced release cycle for Chrome and the rapid evolution of Core Web Vitals, the month of May has been a busy one here at SpeedCurve. With that, we are excited to bring you some new features and enhancements to help you stay focused and ahead of the game as we move into summer.
Read on to learn more about:
I love conversations about performance, and I'm fortunate enough to have them a lot. The audience varies. A lot of the time it’s a front-end developer or head of engineering, but more and more I’m finding myself in great conversations with product leaders. As great as these discussions can be, I often walk away feeling like there was a better way to streamline the conversation while still conveying my passion for bringing fellow PMs into the world of webperf. I hope this post can serve that purpose and cover a few of the fundamental areas of web performance that I’ve found to be most useful while honing the craft of product management.
So, whether you are a PM or not, if you're new to performance I've put together a few concepts and guidelines you can refer to in order to ramp up quickly. This post covers:
Let's get started...
Getting up to speed on Core Web Vitals seems to be at the top of everyone's to-do list these days. Just in time for the holidays, we are happy to bring you our new Vitals dashboard to help you get a huge jumpstart.
We love to visualize performance data (in case you haven't heard). We love it even more when we can be true to one of our biggest motivations at SpeedCurve: leveraging both RUM and Synthetic data to help you take action on what matters most.