It takes as much energy to wish as it does to plan. — Eleanor Roosevelt
There is a growing number of things that we have to do to help the browser achieve for peak performance.
sizes attribute and how big the images are with w descriptors. width and height presentational attributes, which have always been somewhat useful and are now really useful. will-change property in 
Every so often, the fruits of innovation bear fruit in the form of improvements to the foundational layers of the web. In 2015, HTTP/2 became a published standard in an effort to update an aging protocol. This was was both necessary and overdue, as HTTP/1 rendered web performance as an arcane sort of discipline in the form of strange workarounds of its limitations. Though HTTP/2 proliferation isn’t absolute — and there are kinks yet to be worked out — I … Read article
If you're interested in leveling up your knowledge and skill of web performance, you can't do better than learning directly from Scott Jehl.… Read article
Here’s a wonderful reminder from Stephanie Stimac about web performance. She writes about a recent experience of moving to an area with an unreliable network and how this caused problems for her as she tried to figure out what was happening during a power blackout:
… Read articleAssuming all of your customers are living the same life, with the same privilege, with the same access to fast internet and data is the quickest way to ensure you’re excluding some of them and
People say JAMstack sites are fast — let’s find out why by looking at real performance metrics! We’ll cover common metrics, like Time to First Byte (TTFB) among others, then compare data across a wide section of sites to see how different ways to slice those sites up compare.… Read article
I was chatting with some front-end folks the other day about why so many companies struggle at making accessible websites. Why are accessible websites so hard to build? We learn about HTML, we make sure things are semantic and — voila! @— we have an accessible website. During the course of conversation, someone mentioned the Domino's pizza legal case, which is perhaps the most public example of a company being sued because of a lack of accessibility.
Here’s an … Read article
There are all these sites out there that want to help you with your images. They do things like optimize your images and help you serve them performantly.
That's a very good thing. By any metric, images are a major slice of the resources on websites, and we're notoriously bad at optimizing them and doing all the things we could to lower the performance hit from them. So you use some service to help you deliver images better. Smart. Many of them will make managing and optimizing images a lot easier. But I don't consider them a no-brainer. There is a lot to think about, like making choices that don't paint you into a corner.
At a recent conference talk (sorry, I forget which one), there was a quick example of poor web performance in the form of a third-party widget. The example showed a site that installed the widget in order to add a "email us" button fixed to the bottom right of the viewport. Not even a live-chat widget — just an email thing. It weighed in at something like 470KB, which is straight bananas.
Just in case you are someone who feels … Read article
In this week's roundup, Lighthouse sheds light on third-party scripts, insecure resources will get blocked on secure sites, and many country connection speeds are still trying to catch up to others... literally.
Lighthouse, Chrome’s built-in auditing tool, now shows a warning when the impact of third-party code on page load performance is too high. The pre-existing “Third-party usage” diagnostic audit will now fail if the total main-thread blocking time caused by … Read article
WebPageTest is an online tool and an Open Source project to help developers audit the performance of their websites. As a Web Performance Evangelist at Theodo, I use it every single day. I am constantly amazed at what it offers to the web development community at large and the web performance folks particularly — for free.
But things can get difficult pretty quickly when dealing with Single Page Applications — usually written with React, Vue, Svelte or any other … Read article