Table of Contents Introduction What are Beacons? Beaconing Stages Sending Data at Startup Gathering Data through the Page Load Incrementally Gathering Telemetry throughout a Page’s Lifetime Gathering Data up to the End of the Page “Whenever” How Many Beacons? A Single Beacon Multiple Beacons Mechanisms Image XMLHttpRequest sendBeacon() Fetch API Fallback Strategies Payload Limits URL […]
More and more websites are relying on JavaScript for the interactions they provide. It enables pleasant experiences but also comes with undesirable effects: Longer page load times Page is unusable until the JavaScript loads and if it does so without any errors Usability, reactivity and accessibility can be lacking without a team with the means […]
Most Web Performance Calendar posts are about improving client-side web performance. That’s a good thing because I don’t know much about the web—it’s very complicated, naming all those bits and bytes in the browser. Instead, I’m going to talk about something much more transparent: CLOUD performance. In that vein, my parody channeling of the Ray […]
Photo by Coley Christine Working for a company that builds websites for big international brands; these are the challenges I have to deal with as a web performance consultant: Hundreds of people can impact web performance with their decisions — often without knowing it. Stakeholders believe web performance is a technical problem that we can […]
Improving web performance leads to improved conversions and increased profits. There are numerous case studies on this, and often even the non-technical product managers know this fact. So why is it that very often performance is tackled as a last-minute, fire-fighting emergency – possibly after being swamped with negative customer feedback highlighting the website’s poor […]
Intro. A confuse. Have you ever read, or heard sentences like “a company X got NN% increase in revenue when they improved their site speed by YY%”? Or something like this? (Image shamelessly stolen from “Progressive Web App 2016” video) I bet you have. Working on the performance of an on-premise enterprise operational support system […]
In the December 2018 edition of the Performance Advent Calendar, Doug Sillars reminded us that base64 encoding is a performance anti-pattern. But yet, anecdotally, over the last few years I’ve noticed the number of sites with badly implemented data URIs seems to be increasing rather than decreasing. And most of the increase seems to be […]
Image by andrekheren My main focus the last months has been setting up a Wikimedia performance mobile device lab. We started with Android devices and plan to add iOS when Apple pushed our First Contentful Paint time contribution by Noam Rosenthal in Safari and fix a WebDriver issue. You can read all about our setup […]
Introduction What is this? A post with questions and no answers? Close. I still hope you learn something new. At the very least, you can use it as a sort of checklist to improve your web application’s performance. My aim is to go a bit deeper than most online performance tools like Lighthouse and WPT, […]
Photo by Macau Characters: Alice (senior performance consultant): efficient, sometimes brusque, with deep industry experience Carrie (performance engineer): quiet, extremely capable James (junior performance engineer): young, fun, sometimes foolhardy Ankit (senior performance engineer): considered, careful, rarely misses anything Dave (performance engineer): quick-witted, Jan (junior performance engineer): newest member of the team, keen, but unsure of […]
The goal of running a perf A/B experiment is to validate that some performance metrics, such as page load or interaction times, improve. The secondary goal is to establish that other crucial engagement metrics are also improving, such as conversions, cancellations or time spent metrics. For a site that’s already reasonably well-optimized, it can be […]
I hope you didn’t miss the session about The Future Of Core Web Vitals at Chrome Dev Summit 2020. I think it’s great that the Chrome team is open about the metrics and is looking for feedback! When Google Web Vitals first was introduced there were three things that disturbed me: The science behind Web […]
Those who have run into the motherfuckingwebsite-series already know how to build the fastest website. And even if you don’t, it speaks for itself: just use HTML only. Because even CSS is render blocking, and always have been (2012). But such websites aren’t the reality today. To achieve some sort of perceived performance, even when […]
In my work, I like to group reliability, efficiency, accessibility and performance into a category I call “Quality”. All this type of work has a clear benefit to the user and to the business, but it is not always possible to draw a direct line between this work and whatever indicator your team or company […]
Dear fellow web professional, you should be interested in Web Performance. It’s a topic that is at the heart of the web, which needs specialists, and is booming. I know you don’t believe me, or that you think that this is not easy and you’re right. So let me tell you where we stand. and why we need you to join us.
A long time ago, we had a client with a performance problem. Their entire web app was slow. The situation with this client’s app was a bit tricky; this client was a team within a very large company, and often—in my experience, anyway—large companies mean that there are a lot of different people/teams who exert […]
The Web Vitals are a set of web page performance metrics that Google recommends using to better understand the user experience of a given page. They are the latest evolution of web performance metrics away from browser-centric metrics and towards understanding how a page feels to a user when it is loading and being interacted […]
At Wikipedia, we built an efficient sampling profiler for PHP, and use it to instrument live requests. The trace logs and flame graphs are powered by a simple setup that involves only free open-source software, and runs at low infrastructure cost. I’d like to demonstrate that profiling doesn’t have to be expensive, and can even […]
tl;dr: lazy-load non-critical resources when a user interacts with UI requiring it Your page may contain code or data for a component or resource that isn’t immediately necessary. For example, part of the user-interface a user doesn’t see unless they click or scroll on parts of the page. This can apply to many kinds of […]
As the year coming to the end, it would be a lot of posts about technology trends. So I wanted to share my personal thoughts here too – as it appears that we are getting close to drastic changes in performance management. Recently I shared my list of five trends in performance engineering in 2020 […]
Introduction Testing is an important part of software development and especially so for those items that may not be immediately noticeable when they regress. Unfortunately web performance, accessibility, SEO and other best practices all fall into that category. Using an unoptimized image may work fine on your high-spec development machine, on your high speed internet […]
Web applications and API endpoints are known to perform backend calls. Often that is all application does: fetches data from a couple of backends, combines it, and produces response. Monitoring how much time fetching data took is essential. There are plenty production-ready buy-and-snap-on solutions that provide such monitoring, but they might be not good fit […]
A large-scale study of people’s perception of Wikipedia’s page load times.
Chrome team’s quest for measuring abandonment, including a measurement API.
You made a site faster but revenue didn’t improve. Was everything those #webperf people told you a lie?
Head-of-Line Blocking in QUIC and HTTP/3: The Details As you may have heard, after 4 years of work, the new HTTP/3 and QUIC protocols are finally approaching official standardization. Preview versions are now available for testing in servers and browsers alike. HTTP/3 is promising major performance improvements compared to HTTP/2, mainly because it changes its […]
Swap? Fallback? Optional? Which font-display setting should you pick? Let Matt walk you through the considerations.
Web performance can mean a lot of different things to a lot of different people. Fundamentally, it’s a question of how fast a web page is. But fast to whom? When this page loaded moments ago, was it fast? If so, congratulations, you had a fast experience. So ask yourself, does that make this a […]