Path to Performance is a podcast with Tim Kadlic and Katie Kovalcin. They interview a guest and discuss how to improve web performance. Because I’ve listened to all the episodes, I thought it would be helpful to organize my thoughts about them with a summary of each one. I think this will be a value-add to the show notes page. Please let me know if you think this is useful or not to you in the comments
In this episode, Tim and Katie interview Lara Hogan, the head of engineering (check title) performance at Etsy. They talk about how to build a performance culture and how to win influence for performance considerations.
Pre-interview
Tim talks about What Does My Site Cost?, a tool built on top of WebPageTest to show developers how much their site costs for a mobile user to load. The price can also be adjusted by other factors, like percentage of gross national income to get a better sense of what it’s costing real users.
Perf audit is a place with bite-sized performance audits online. Paul Irish published an in-depth performance audit that uses Chrome developer tools extensively.
History of performance at Etsy
Before Lara took the position, another engineer, Seth Walker started promoting performance by
putting data in front of engineers: he let them know how well parts of the site were performing. This led to greater performance buy-in from the team. Lara mentioned that there’s also buy-in from upper management: the CEO was the CTO and had a strong desire to see a performant site. This set Lara up for the work that she is doing now.
How performance is promoted at Etsy
Lara talked about how important it is to create a performance culture: it won’t stick if it’s just all top-down, “The CEO said to do it.”
One way is to push performance forward by using ego (and WebPageTest). Lara points out that for most audiences, waterfalls are boring, filmstrips (images of the site loading over time) are okay, but videos of the site loading can create a visceral reaction to slowness. Show a competitor’s loading video against your own. This gets people invested in speeding up their part of the site.
Find stats that the business cares about and equip them to measure performance changes against those metrics. Check what the performance experience is for users in other countries.
Another way to cultivate this culture is to celebrate performance wins. Find a person who has done performance work and highlight them and cheer on their success. At Etsy, this is done by putting out a picture them with the performance group looking ecstatic.
Celebrating performance brings the benefits of being a cheerleader for performance as opposed to a enforcer or janitor. A culture change will be more effective with positivity.
Design and performance
Lara wrote Designing for Performance, seeking to put out a concise resource for people who don’t need to know the ins and outs of the browser’s render path, but still want to put together performant solutions. At Etsy, she’s continually educating the designers about performance-related topics at a level that’s relevant to them. She doesn’t need them to know why one image format is better in certain situations, just that it is a consideration and where the resources are to make that decision.
Keeping performance going
At Etsy, they monitor production real user metrics (RUM) on their the site for performance regressions. When the system discovers a regression, it alerts the performance group. The performance group reaches out to the owning team and offers consulting help. They still expect the owning team to do the work and the fix the problem. Etsy also has synthetic tests that run over time to track long term trends.
One longer term goals is to monitor and alert for improvement so that wins can be celebrated.
Continuous improvement
One challenge is setting SLAs that don’t punish teams for success: Laura gives the example of a team that got back end time page down from 800 ms to 400 ms. Do you set a new SLA at the new normal or not? Things will get slower, so probably not. Etsy does have different SLAs for mobile and desktop.
They’re also actively looking to increase the performance of the native apps. She has proposed some ways to objectively measure how performant your native app is.
Another way to improve things is to make your own team feel the pain of users on slow networks: throttling the speed of the office network to something lower, for example.
Wrapping up
Lara stated that she’s very thankful for the freedom she has at Etsy to experiment and all the tools and infrastructure. She and the rest of the team at Etsy give back through their blog and their open source projects. She encouraged people to check out her book and that the proceeds go to help girls learn to code.
I encourage you to check out the episode as well as the links and transcript available on Path to Perf’s site!