Foreword

“May you live in interesting times,” goes the old half-curse. And I don’t know about you, but it feels like the web is perpetually stuck in interesting times. We’re designing for an ever-expanding number of mobile devices, each one more powerful than most laptops I’ve owned throughout my career. But we’re also designing for a web that travels over the aging infrastructure of developed economies, as well as to cheaper, low-powered mobile devices in younger, emerging markets.

In other words, the web is more broadly accessed today than ever before—but over a network that’s far more fragile than we might like to think. Once a user requests one of our web pages, any number of things can fail. Maybe a connection drops, or a network’s latency is too high for an asset to load. Or maybe the users exceeded their data allotment for the month.

We’re building digital experiences—some responsive, some not—that are more beautiful than anything produced at any other point in the web’s history. But we need to start designing for performance as well. We need to create sites and services optimized for the fragility of the network, as well as the widths of our users’ screens.

Thankfully, you’ve begun reading Web Performance in Action, a book that can help you do just that. Jeremy Wagner has written an invaluable, accessible reference for the modern web developer, one that demystifies even the most arcane-sounding acronyms and frames even the most arcane-seeming web optimization tricks in approachable, plain language. In interesting times like these, Jeremy’s guide is indispensable: As you travel through these pages, you’ll gain the skills to ensure your sites are as beautiful as they are fast, nimble, and bandwidth-friendly.

Ethan Marcotte

Designer, Ethanmarcotte.com

Author of Responsive Web Design