Build resilient systems at scale
May 27–29, 2015 • Santa Clara, CA

What are third-party components doing to your site?

Andy Davies (NCC Group), Simon Hearne (NCC Group)
2:40pm–3:20pm Thursday, 05/28/2015
Location: Mission City M1-2
Average rating: ****.
(4.86, 7 ratings)
Slides:   1-ZIP    external link

Prerequisite Knowledge

Some understanding of the way web pages are built and the types of third-party components in use.


We increasingly rely on third-party scripts to deliver some of the business-critical features of our sites – analytics, adverts, multi-variant testing, comments, recommendations, retargeting, social sharing etc.

Often these scripts get added with the seemingly innocent “it’s just a snippet of JavaScript,” but they can have a dramatic impact on performance, from slowing the page down to completely breaking it when a third party has availability issues.

Despite this explosion in third-party components there’s little information on the value they deliver, how they interact with our sites, and what their impact on performance is.

In this session we’ll share the insights we’ve gained from analysing the impact third-party scripts are having on performance of the sites we monitor, the value they deliver, and how our clients manage them.

We’ll look at which third parties are the most popular, how they interact with our pages, and how consistent their performance is.

Attendees will come away with a better understanding of third-party performance, and pointers to how to make informed decisions when choosing third parties.

Photo of Andy Davies

Andy Davies

NCC Group

Andy is associate director for web performance at NCC Group, working with clients to measure and improve the performance of their websites. He recently wrote the “The Pocket Guide to Responsive Web Performance” for Five Simple Steps.

Andy is co-author of O’Reilly Media’s Using WebPagetest. Learn more.

Photo of Simon Hearne

Simon Hearne

NCC Group

Simon is a web performance technical consultant at NCC Group, where his time is split between helping clients improve their web performance, and working on exciting new projects. Simon studied artificial intelligence and web science before joining NCC Group.