Tammy Everts 🍁

@tammyeverts.com

2267 Followers 333 Following

I contain multitudes, but for brevity: reader, writer, speaker, baker, quilter, yoga-er, mom-joke teller, lover of lakes and mountains. 🫶 Building #UX / #webperf / #o11y community at @embrace.io (which acquired @speedcurve.com) 🫶 Co-chair of @perfnow.nl

Shoresy from Letterkenny skating backward at a hockey rink.
These four slime molds – with the scientific name elaeomyxa ceriferaour – look like spheres with iridescent surfaces ranging from green to blue to purple.
A time series chart that shows how a web performance budget works. This chart tracks Cumulative Layout Shift (CLS). Over time the metric fluctuates. The performance budget is represented as a red horizontal line across the chart, which is the predetermined ideal maximum threshold for the metric. When the CLS metric is greater than the budget, it's highlighted in red. When the metric improves and drops below the budget, it returns to normal.
Pictorial graph that shows relative weight of images on web pages, according to the HTTP Archive. The median page has 1053 kilobytes worth of images, while the 75th percentile page has 2892 kilobytes and the 90th percentile page has 6888 kilobytes.
Sculpture by Canadian artist Elaine Brewer-White of a large grizzly bear gently cradling Deadpool.
Photo of the tarmac at the Vancouver airport, taken from a hotel room window.
A rainbow over Amsterdam.
A pretty white dog dressed up for Halloween, wearing a black witch’s hat and a purple tutu.
Classic image of Charlie from the tv show It’s Always Sunny in Philadelphia standing in front of a whiteboard covered in conspiracy theory scribbling.
Performance expert Andy Davies on stage at the performance.now conference in Amsterdam.
SpeedCurve performance expert Andy Davies on stage at the performance.now conference in Amsterdam.
Performance expert Andy Davies on stage at the performance.now conference in Amsterdam.
Performance expert Tim Kadlec on stage at the performance.now conference in Amsterdam.
Performance expert Tim Kadkec on stage at Performance.now conference in Amsterdam.
Chocolate bars
Ethan Gardner on stage at PerfNow
Performance expert Ethan Gardner on stage at the performance.now conference.
Ines Akrap on stage at the performance.now conference in Amsterdam.
Web performance expert Ines Akrap on stage at the performance.now conference.
Chocolate bars!
Accessibility expert Marcy Sutton Todd on stage at the performance.now conference in Amsterdam.
Accessibility expert Marcy Sutton Todd on the stage at the performance.now conference in Amsterdam.
Quote from Catherine Jue: "Fast eliminates cognitive friction. Raycast surfacing the right application before you finish typing feels like an extension of your mind. Superhuman's sub-100ms rule — plus their focus on keyboard shortcuts — changed the email game in a way that no one's been able to replicate, let alone beat... No one praises these tools explicitly for their speed. They just feel magical."
A screenshot of a chatbot window, with the following message: "Hello! I am your AI assistant ready to help you. How can I guide you today?" This is followed by the deflating message: "All chat agents are currently busy."
Stephen Hawking quote: "“One of the basic rules of the universe is that nothing is perfect. Perfection simply doesn't exist. Without imperfection, neither you nor I would exist."
Friendly-looking humanoid alien – we call him Herman – sitting on a park bench, using the internet on his laptop.
Screenshot of the AccuWeather app loading screen: a white sun icon on an orange background.
Partial screenshot of an app, with the logo intentionally cropped out. What you can see is that the app has an orange background, and that it was accessed over a 3G network.
A very pretty white dog with perked-up ears standing on a sandy beach on a sunny day.
Woodcut illustration of a star-nosed mole, a small mammal with large front claws and tentacle-like appendages around its nose.
A blue book cover. The title of the book is Time is Money: The Business Value of Web Performance". The author is Tammy Everts.
Screenshot of Google Maps skeleton screen, showing how content doesn’t render with an LTE connection.
Screenshot of LinkedIn skeleton page, not rendering because device is on a 3G connection.
A screenshot of an unresponsive web page, which is blank except for a progress indicator.
Screenshot of Google Translate for French-to-English translation.
A table that shows how a handful of web performance metrics – Time to First Byte, Start Render, Largest Contentful Paint, Cumulative Layout Shift, and Interaction to Next Paint – stack up against these criteria: Correlates with meaningful content in the browser. Usable out of the box. Broad browser support. Available in both synthetic and real user monitoring. Correlates to business and UX metrics (like conversions and bounce rate).
Three popular web performance charts. 1. Correlation chart that shows the relationship between page speed metrics, like start render or Largest Contentful Paint, and business metrics, like conversion rate. 2. Waterfall chart that shows a visual timeline of all the resources on a web page, from HTML to images to JavaScript, as they're loaded and rendered in the browser. 3. Competitive benchmarks chart is a leaderboard that ranks your site alongside your competitors, so you can see who's faster and who's slower.
Screenshot of an excerpt from George Orwell's essay "Politics and the English Language". The excerpt reads: "Each of these passages has faults of its own, but, quite apart from avoidable ugliness, two qualities are common to all of them. The first is staleness of imagery; the other is lack of precision. The writer either has a meaning and cannot express it, or he inadvertently says something else, or he is almost indifferent as to whether his words mean anything or not. This mixture of vagueness and sheer incompetence is the most marked characteristic of modern English prose, and especially of any kind of political writing. As soon as certain topics are raised, the concrete melts into the abstract and no one seems able to think of turns of speech that are not hackneyed: prose consists less and less of words chosen for the sake of their meaning, and more and more of phrases tacked together like the sections of a prefabricated hen-house. I list below, with notes and examples, various of the tricks by means of which the work of prose-construction is habitually dodged."
Screenshot of a section of a tech blog post. the text reads: What Are Core Web Vitals? Core Web Vitals refer to a certain set of measurable metrics that Google applies to judge whether end-user experience on your site is in reality satisfactory. These Core Web Vitals consist of the following three operating parameters beginning in 2025: 1. Largest Contentful Paint (LCP) Measures loading performance. Specifically, it gauges the time it takes for the most significant visible content component (like an image or title) to display to the user. Good score: Anything less than 2.5 seconds! 2. Engagement to Upcoming Render (EUR) (launched in 2024, substituting FID) Measures responsiveness. It essentially measures the input delay; hence, it considers the maximum input delay. Good score: Under 200 milliseconds 3. Cumulative Layout Shift (CLS) Measures the visual stability of a page. It tracks how much content shifts unexpectedly during page load. Good score: Less than 0.1 Having these metrics are essential to ensure a seamless, frustration-free experience under every device and connection type.
Split-screen image of me, Tammy Everts, a white woman with brown hair, standing on stage at the WebExpo Conference in Prague, with a slide from my talk alongside. The slide reads: "Web Stress: When apps or sites are slow, we concentrate up to 50% harder to stay on task."
Performance expert Tim Kadlec on stage at the WebExpo conference in Prague.
Video of an aerial silks dancer performing at the opening of WebExpo in Prague.
Old buildings in central Prague, shortly after sunrise.
Ominous dark thunder clouds above an historic building in Prague.
Five very cute puppies wearing party hats.
Side-by-side snapshots of two points on the page rendering timeline for Lufthansa.com on a mobile device. The Start Render frame is mostly empty at 3.9 seconds. The Largest Contentful Paint frame shows a consent banner at 21.75 seconds.
Leaderboard showing rendering timelines for 10 leading travel sites, tanked from fastest to slowest Largest Contentful Paint time. Trivago is fastest and Kayak is slowest.
Screenshot of the Page Speed Benchmarks leaderboard for travel sites in the EU and UK. It consists of a set of stacked rendering filmstrips, ranging from fastest to slowest website. The fastest is Trivago. The slowest is Lufthansa.
Screenshot of the Page Speed Benchmarks leaderboard for travel sites in the EU and UK. It consists of a set of stacked rendering filmstrips, ranging from fastest to slowest website. The fastest is Trivago. The slowest is Lufthansa.
Correlation chart that illustrates the information described in the post.
Correlation chart show that as pages get slower for this site, conversion rate (predictably) decreases. The cohort of users who experienced Largest Contentful Paint times of 1.1 second also had the highest conversion rate – more than 6 percent!
Photo of me (Tammy Everts), a white woman with brown hair. The caption includes the following details about my conference talk at WebExpo: May 29th at 3pm. Talk title: Connection the dots between site speed, user happiness, and business success.
Pie graph that shows the breakdown of Chrome browser usage: 88.2% of Chrome users use a version that is less than 12 months old. 11.15% use a version that is between 1 to 5 years old. 0.52% of Chrome users are currently using versions that are between 5-10 years old.
Column chart showing the potential average revenue loss of $21,000 due to site outages compared to $41,000 for site slowdowns.
Screenshot of a competitive benchmarking leaderboard, featuring Amazon, Etsy, IKEA, LEGO, and Walmart.
Screenshot of a synthetic page test waterfall chart, which shows that the main hero image on the page is the fifth resource request.
A group of three business people – a white woman, a Black woman, and a Black man – who are all smiling. Above their heads is a word bubble that says "We worry about all the money stuff so you can get paid."
Screenshot of text that reads: Interaction to Next Paint (INP). Limited browser availability. INP measures the time from when a user initiates an interaction until the next frame is painted. Only the following interactions are observed: mouse click, touchscreen tap, and a physical or onscreen key press. INP has replaced First Input Delay (FID) as a core web vital as of March 2024. Interaction to Next Paint is one of Google's Core Web Vitals, along with Largest Contentful Paint and Cumulative Layout Shift.
Graphic of an odometer with the needle deep in the red zone. Caption reads "current Schadenfreude odometer".
Light text on a blue background, which reads: "If you could measure the impact of site speed on your business, how valuable would that be for you?"