Learn about web performance from the experts. These videos provide a wealth of knowledge about how to make web pages faster.

Everyone knows what happens when a page loads slowly: the visitor leaves. That much is simple. But what is not always so obvious is what to do when you have addressed the “low-hanging fruit.” There are a number of variables at play with regard to page load time and at times it can be a bit tricky to understand how to measure and analyze each one. In these talks, you’ll find discussions that go beyond CSS sprites and domain sharding. Sure, those techniques (and other similar ones) are almost always helpful, but there is a deeper level of understanding required when trying to get page load speed down to a few seconds. I’ve not attempted to list every helpful video out there; there are many. This list includes the videos that I feel provide the most helpful review of topics. In each case, I’ve found the speaker to have not only a super-expert level of knowledge / experience, but an ability to translate their expertise into an enjoyable presentation.

Optimizing networking performance (and HTTP 2.0) – Crash course on web performance (Fluent 2013)

Ilya Grigorik covers a wide range of topics that define the technology of web performance. There is a healthy percentage of time spent on mobile, including some very deep concepts such as radio optimization and periodic transfers (beacons), and how they consume more battery life than you might expect. One area that is particularly interesting is the TCP/IP “slow start.” Here Ilya explains why the slow start exists (i.e. it’s actually a feature, not a bug), and how it affects performance.

Bandwidth, latency, and radio performance – Crash course on web performance (Fluent 2013)

If you think you understand what happens when you open a web page on your mobile device, think again. Ilya Grigorik goes into incredible detail when explaining what happens in the life of a mobile web request. A highlight is a very helpful explanation of the difference between bandwidth and latency. In addition, he discusses the psychological / business ramifications of delays of more than 300ms. This is a super in-depth talk and very much worth the time if you are interested in the more subtle areas of web performance.

Steve Souders: High Performance Mobile

Web performance guru Steve Souders give a talk that is still every bit as relevant as it was in in 2011. In addition to talking about his famous “14 Rules for Web Performance,” Steve discusses the prevalence of re-directs, domain sharding and the implications of slow JavaScript. In addition, there are discussions about responsive images, app cache, leveraging async JavaScript calls, and downloading JavaScript without executing it (eval alert! : – )

Steve Souders on Web Performance: How Fast Are We Going Now?

One area of this talk that I find interesting is where Steve talks about barackobama.com and how when they improved the speed of the site by 60%, they found that there was a 14% increase in donation conversions. He also talks about trends in connection speeds, performance differences between browsers (including how JavaScript affects this), and his work with HTTP Archive.

Web Performance Testing at YouTube

Rick Viscomi’s high-level discussion or Real User Monitoring (RUM), and Synthetic Testing is fantastic. As a UX engineer at Google/YouTube, his expertise and insights on performance is extremely helpful. Rick explains Google’s approach to client-side instrumentation (CSI), and how their “measure / beacon / analyze” approach works. He also talks about how Google uses WebPageTest for synthetic testing.

Speed Up Your JavaScript

Some may feel that web performance is only about reducing HTTP requests and leveraging CSS sprites, but when you consider that when any external JavaScript file referenced by a script tag is downloaded and parsed, the page is completely blocked. Although this video is more than five years old, it is a must for any JavaScript developer. Nicholas Zakas talks about Scope management, Data access, loops and DOM access in the context of performance. He also does a deep-dive into what actually happens when a function executes and how that affects performance, how the “with” statement and “catch” clause of the try-catch statement affect the scope chain, as well as performance implications of “for”, “while” and “do while.” There is also a discussion of the tricky behavior of HTMLCollection objects, eflow events, and how the DocumentFragment object can help improve performance.

Mobile Web Performance

Guy Podjarny, CTO of Web & Mobile at Akamai gives a great talk about mobile web performance. This video is nearly three years old, but still relevant. Guy’s perspective is particularly helpful because of his work in Akamai and the experience in that domain.