Performance Rule #1: Do What You Need to Do—But Not More

Published on November 13, 2018 (↻ July 14, 2023), filed under Web Development (RSS feed for all categories).

Web Performance has over the age of the Web not only turned into a discipline by itself, but also a complex one at that (and one that can but shouldn’t be seen in isolation).

While important much less so for revenue (higher speed correlates with higher conversions) but for user experience (a fast site or app feels instantaneous, whereas a slow one may get abandoned) and accessibility reasons (hundreds of millions of people access the Internet on slow mobile connections), there’s a particular angle at performance that makes the matter very simple: the pragmatic one.

This angle says: Just do what you need to do. But not more.

Which means: Publish the content you need to publish. Write the code you need to write. Use the assets you need to use. Embed the third party styles and scripts you need to embed. But don’t do anything more than that.

It’s a simple and effective rule addressing all our performance aspirations—as long as we know what we need.

That, then, seems to be our true performance challenge. Very often, we do not know exactly what we need.

We may not know what contents should really go on each page (though that one, for many of us, is a decision made by the content owners we’re working with). We may not know what code we need, and truly need ^*. We may not know what assets, multimedia that is, are really crucial and which ones aren’t, or how they’re all delivered most effectively. We may not know that we don’t need a reset or what part of jQuery we feel we require is long part of native ECMAScript. We may not know.

This translates to an interesting situation, then: Performance can be a very simple matter once we understand what we actually, really, truly need ^†. For content, and for code. Because once we understand that, we can stop right there, and refuse to add more contents, write more code, and embed more resources. Because on the other end, performance has never been about leaving out what one truly needed. It’s always been about what more one could leave out—what one can omit, defer, cache, and compress. And only there, with rules #2 and up, things get more complicated.

^* The unpopularity of omitting optional tags, a by now ancient markup optimization concept that hooks up on actual HTML necessities, may be a good example for this. Other ones are JavaScript support and favicons.

^† Not surprisingly, external frameworks come with a performance tax for precisely this reason, which I elaborated on in detail in The Little Book of HTML/CSS Frameworks (updated) and its school of tailoring.

About Me

I’m Jens, and I’m an engineering lead and author. I’ve worked as a technical lead for companies like Google and as an engineering manager for companies like Miro, I’m close to W3C and WHATWG, and I write and review books for O’Reilly and Frontend Dogma.

With my current move to Spain, I’m open to a new remote frontend leadership position. Feel free to review and refer my CV or LinkedIn profile.

I love trying things, not only in web development, but also in other areas like philosophy. Here on meiert.com I share some of my views and experiences.