Performance Hero: Annie Sullivan

Let's kick off the new year by celebrating someone who has not just had a huge impact on web performance over the past few years, but who has even more exciting stuff in the works for the future: Annie Sullivan!

Annie leads the Chrome Speed Metrics team at Google, which has arguably had the most significant impact on web performance of the past decade. We've gotten to know Annie through frequent discussions, feedback sessions, and hallway talks at various events. Most recently we caught her closing keynote at performance.now() in November. 

Speaking from experience, driving change at scale from within a large organization can be very challenging. Annie and her team navigate this arduous task with true passion for web performance and for improving the user experience. Read on for a great recap of a recent discussion with Annie and just a few of the highlights that make her a true performance hero.

In her recent performance.now() talk, which is a must-watch, Annie took us through key learnings she has had while working in performance for the last couple of decades.

In her preamble, she celebrated some of the successes our community has had over the past year. This slide really stuck out to me as an example of how we collectively have a huge impact on the user experience:

You know when you are measuring success in 'years of time saved' that you've had a meaningful impact. Nice job, everyone!

It's really important to acknowledge that none of this would have been possible without the great work from Annie and her small-but-mighty Speed Metrics team at Google. Here is a little more we learned about Annie and her team.

How did you get your start in web performance?

"The very first web performance project I did was back in the late nineties! I was running a message board for the local punk rock scene in Detroit. I started with WWWboard, but it had a race condition that led to overwriting posts. So I decided to write my own message board in PHP and MySQL, which better managed transactions. But my original version was slow, because I queried the database for every page load. Of course writes were much less common than reads, so I added a caching layer for reads, and that did the trick.

"After I finished college, I did performance work here and there while developing games for Playstation 2, and later at Google. Then in 2008, Google issued a code yellow for application speed, and I was the code yellow lead for Google Docs. A critical part of the code yellow was ensuring Google's sites would be fast for users across the globe, even if they had slow networks and low end devices. Leadership wanted to know the real page load times end users were experiencing. So in addition to all the optimization work we did for Google Docs, I got to spend a lot of time and energy working on the measurement problem: how can we get end-to-end latency numbers? How do we slice and dice them to find problem areas? What should we tell browser vendors is missing? That got me started on a long journey I'm still on today."

(We always knew you were punk rock, Annie, but we had no idea you'd been at performance since the nineties!) 

What is the charter of the Chrome Speed Metrics team?

"The Chrome Speed Metrics team aims to quantify users' experience of the web to provide Chrome engineers and web developers the metrics, insights, and incentives they need to improve it.

(At SpeedCurve, we've worked closely with this team over the years, and can tell you that everyone is invested in this mission. The Speed Metrics team is a great example of how to build a performance first culture within your organization, whether that's a ginormous company like Google or a small shop like SpeedCurve, passionate people truly can make a difference.)

2024 seemed like it was full of big wins. What was the one you were most proud of?

"With the introduction of the Long Animation Frames API [LoAF], sites have better insight into the causes of slow JavaScript than ever before. With the additional data, we've been able to reach out to several third parties who've then made improvements, and I've heard positive stories from several other members of the web perf community who've done the same. There were two case studies highlighting third party wins published on web.dev (1, 2), and Google Publisher Tag launched a new yielding strategy. All the feedback from third parties we got from this process helped us prioritize the scheduler.yield() API so that it's easier for third parties to work well with the rest of the content on the page.

"I know third parties have long been a point of frustration for web performance enthusiasts, but it's been amazing to see the optimizations here, which can make thousands or even millions of sites faster overnight."

(We agree the visibility that LoAF attribution brings is exciting! Everyone loves to hate third parties, but with the exception of synthetic testing, we haven't had a lot to work from. SpeedCurve is hard at work looking at how to leverage the LoAF API to improve our RUM data. We hope that third parties embrace this data and continue to look at improving. However, we are also hearing that a fair number of LoAFs responsible for poor Interaction to Next Paint (INP) are surprisingly coming from first-party JavaScript!)

What are you working on now and/or what are you most excited about?

"I'm currently working with Michal Mocny [on the Google Speed Metrics team] on integrating soft navigations into Core Web Vitals. I'm really excited about getting a deeper understanding of single page applications and their performance. From my perspective, it's the biggest blind spot in web performance and every day I learn something new."

(We've been following this work closely and are thrilled to see it getting so much attention. SPAs continue to be a challenge for performance, starting with measuring the true user experience. Looking forward to seeing this evolve!)

As we roll into 2025, what do you see as the single biggest challenge in front of us?

"I always get excited about challenges, and I think the biggest one is working together! There are so many wonderful developments in the world of standards--increased engagement from other vendors, the RUM CG, the Container Timing work. I'm excited for the challenge of collaborating effectively with people around the world. There's so much potential to bring many more viewpoints to the table."

(Well put, Annie. We couldn't agree more. And here's a shameless plug for the W3C RUM Community Group, which has generated a lot of interest and had its first meeting on January 17. Learn more about the RUM Community Group.)

We are soooooo excited for 2025, especially with awesome leaders like Annie at the helm. 

Do you have someone you'd like to recognize as a Performance Hero in 2025? Let us know!