Building a Better Web
June 11–12, 2018: Training
June 12–14, 2018: Tutorials & Conference
San Jose, CA

Raiders of the fast start: Frontend performance archeology

11:00am–11:40am Thursday, June 14, 2018
Performance and UX
Location: 210 A/E
Secondary topics:  Case study, Web Pillars Track: Performance, Security, Accessibility
Average rating: ****.
(4.40, 5 ratings)

Who is this presentation for?

  • Web developers and those working in UI/UX

Prerequisite knowledge

  • Familiarity with client HTML, CSS, and JavaScript
  • Basic knowledge of performance best practices (useful but not required)

What you'll learn

  • Learn how Etsy uncovered and fixed performance issues in its mobile product page code


There are a lot of books, articles, and online tutorials out there with fantastic advice on how to make your websites performant. It all seems so easy in theory, but applying best practices to real-world code is anything but straightforward. Diagnosing and fixing frontend performance issues on a large legacy codebase is like being an archaeologist excavating the remains of a lost civilization. You don’t know what you will find until you start digging.

Pick up your trowels and join Katie Sylor-Miller to dig into frontend performance on Etsy’s large legacy mobile codebase, exploring real-life lessons you can use to guide your own excavations into legacy code and discovering how Etsy unearthed new insights into its culture. While Etsy prides itself on its culture of performance, like all cultures, it needs to adapt and reinvent itself to account for changes to the landscape. The company is now making the case for a new, organization-wide frontend-focused performance culture that will solve the problems we face today.

Topics include:

  • The open source tools and metrics Etsy used to diagnose issues and track progress
  • How Etsy went beyond server-driven best practices to focus on the client
  • The tools Etsy built to help find and delete old, unused code
  • Which fixes successfully increased conversion and which didn’t
Photo of Katie Sylor-Miller

Katie Sylor-Miller


Katie Sylor-Miller is a staff software engineer on the frontend systems team at Etsy, where she advocates for and implements frontend best practices in collaboration with product engineers and designers. She is passionate about frontend architecture, design systems, style guides, accessibility, performance, and teaching others. Katie has written about the engineering side of design systems for the Design Systems Handbook, and she created to share her hard-won knowledge of how to get out of your Git messes with a bit of humor (and a lot of swears).