Last week I realized it was time to switch gears. Keeping this weekly “mini blog” for 3+ months has helped me gather my thoughts. Now it’s time to move into the next phase: work. You can read the latest draft of Catching Up With Web Performance at https://catchingup.dev. For all future updates, I have a new, dedicated newsletter: https...

How a Car Works is an incredible resource—literally building an entire car from scratch, starting from the engine block. And it’s amazing how often “performance” comes up. Building a car, performance is constantly top-of-mind. How does the block’s material affect its fuel economy? How does vibration in the crankshaft affect RPM? It’s a...

I’ve been getting back in the weeds of things, raw engineering instead of just theorizing. It feels good to get my hands dirty with code, feel the pain of everyday problems (“Why isn’t webpack working?” “How come my CSS won’t load?” “How am I supposed to…?”). How do we talk about performance at this raw, everyday level? Abstractions ar...

Most of the time, performance tuning is about fixing problems. The site was slow, the checkout was unavailable, etc. Like a doctor trying to diagnose an illness, we jump into a situation with little context, searching for clues to what could be causing the problem. Metrics are tests that help narrow down causes. “They have a high LCP? ...

Performance is an infinite game. One of the most interesting aspects of performance to me lately is how it doesn’t stop. It goes on. It’s long. It’s historical. Like, we’re keeping track of this now! (Just look at those CrUX dashboards!) And the time scale isn’t just day-over-day, or week-over-week. No, it’s month-over-month, pushing y...

When you say “Jump”, performance says “How high?” It’s not just the thing you do, it’s how well you do it. Functional requirements focus on what you do (your function) while non-functional requirements focus on how you do it, on the quality of that thing you’re doing. It’s a subtle but powerful shift in thinking: • The car drives, but ...

How do you decide what to measure? It’s a question I keep circling around. Sure, we have metrics other smart people told us to use, but how should we use them? How do I know they matter to me in my situation right now? How do I know when they’re not enough? A game I’ve started playing is “Who did it better?”—but for website functionali...

You’re trying to make something better. How do you know it’s better? At the core of every performance metric is a belief, a fundamental belief about what makes something good. Some things are obvious—a vacuum cleans, a flashlight lights—but most things worth measuring are anything but obvious. Most of the time what we want to measure i...

Good metrics have causality. They tell stories. They say “if this then that”. They clearly measure progress towards a specific goal: run fast win race, study hard pass test, save money buy house, etc. Goals say where you want to go. Strategies say how you plan to get there. Metrics measure your progress, and objectives are like checkpo...

When you’re driving, what information do you keep in front of you? What’s so important that you’d put it on your dashboard? “I need to know X, Y, and Z.” In the car, you definitely want to know your speed, and you want to know how much gas you have left. What else? There’s other information you need access to (like the volume of the ra...

Why don’t we just use the same metrics for every website, every business? The answer sounds obvious when you first ask—“Because they’re different, duh!”—but that’s an awfully hollow answer. Fundamental questions like this deserve more attention. If every business needs money to survive, why not just measure all businesses by the money ...

What if we translated Core Web Vitals to the restaurant world? What would those metrics look like? Here’s my first stab at it: • Time To Menu: From the moment a customer walks in to the time they can read the menu. • First Waiter Delay: The delay between a customer trying to and actually getting a waiter’s attention. • Cumulative Table...

Why “vitals”? Why measure heart rate when what really matters is winning the race? After all, vitals don’t prove you’re alive, they just say you’re not dead. How do you measure success? In a perfect world, if you could measure anything, how would you measure your performance? Often times, we can’t measure exactly the thing we want. Tak...

Lately I’ve been thinking about what web performance measures, what it could measure, what it should measure… Why load time metrics? Well, for one, that’s all websites used to do! But since then, the Web has grown to do so much more. Are we stuck in the past? I don’t think so. There’s plenty of discussion—especially with Core Web Vital...

The scale and power of the Web today is mind boggling. The number of things you can do with it is, in theory, only limited by the number of things the devices connected to it can do. And today’s technology can do, well, almost anything. (Just imagine the technology of tomorrow!) Someone makes something, puts it on the Web, and all of a...

Well, it’s a global information system. It exchanges information between people. It connects people. It’s a communications system. It is “the universe of network-accessible information, the embodiment of human knowledge”. https://www.w3.org/WWW/ “The social value of the Web is that it enables human communication, commerce, and opportun...

Kinds of performance describe either the things you’re trying to do well (the activities) or the thing you’re trying to make better (the subject). You can measure “financial performance” (how well you do financial things) or “business performance” (how well your business works). The interesting thing about subject-based performance (as...

What is “performance”? And what about performance makes it “web performance”? Because performance comes in kinds. At the very least, we’ve had business performance and economic performance since long before we had the Web. Even if you focus on a single object, you can measure all sorts of different performance for it. For example, a ca...