If you've ever wondered who's behind the technical side of RUMvision, it's Erwin. CTO, co-founder, Google Developer Expert, and international speaker. He built version 1.0 during his paternity leave, in the hours when his daughter Hannah was asleep. Four years later, with 2.0 now live, his role is changing. And that's precisely what he wanted.
This interview was conducted by Lars Meijer (Lurz). It is the final interview with the owners of RUMvision, so you can get to know us a little better.
Erwin, how do you usually explain what you do?
I tell people I make websites faster. If that doesn't land, like when I'm talking to my aunt at a birthday, I try a different angle. I say: when you visit a webshop and feel frustrated, I help developers figure out what's causing that frustration and how to fix it. That's the short version.
RUMvision started during your paternity leave. What happened?
We first tried outsourcing the development. That was quite an investment, and we ended up with something that barely worked. You couldn't even create a user account without running into bugs. I thought: I'm a developer myself, I can do this faster. So during my paternity leave, while Hannah was sleeping, I started building. I stripped down our existing CMS, used it as a boilerplate, and just started coding. We moved fast after that with new features, dashboards, and world maps showing real data. Roderik didn't hesitate. He said: let's keep going with this.
What if Hannah hadn't been such a good sleeper?
Karlijn and I have talked about that. There's a very real chance RUMvision wouldn't be where we are now. We probably would've pulled the plug on the whole thing. Building software without doing it yourself was expensive back then, and there was no AI to help. Everything was written by hand. If I hadn't had those quiet hours at night, I don't think RUMvision would exist.
You've described yourself as an introvert who became a public speaker. How did that happen?
I still find that a bit strange myself. My mother-in-law once pointed out that I was always the quiet one at her kitchen table. And yet, I was giving talks to 50, 60 or even 80 people. At some point I just decided: if I want to reach a different audience, I need to put myself out there. So I pitched myself as a speaker. It worked.
What was your biggest stage moment?
Performance.now() in Amsterdam, 2024. It's the biggest web performance event in the world. The people who invented the technology we were presenting about were sitting in the audience. That's a strange feeling. It’s like giving a lecture to the people who could correct you on every detail. But the day before, another speaker said something like: "If only there was a way to measure third-party impact." And that was exactly what we were going to talk about the next day. That's when I realized: okay, we actually have something to say here. The nerves disappeared.
You're known for your hats and bow ties. Where does that come from?
Life can be a bit colorless sometimes. A hat or a bow tie adds something. And Karlijn loves wearing dresses. I can't just stand next to her in boring jeans. At the Webwinkel Vakdagen a few years ago, I deliberately dressed like my LinkedIn profile photo. More than ten people came up to me and said: "You're Erwin, right?" Some even wanted a photo with their team and me. That was the moment I stopped being sceptical about personal branding.
With 2.0 live, what changes for you?
A lot. I built V1, so I always felt directly responsible when something went wrong, even when it wasn't my code causing the issue. I was the first person people looked at. I sometimes compare it to being a goalkeeper: you're the one everyone blames when the ball goes in, even if the defence let it through. That weight is off now. I'm still involved in the tracking snippet and the infrastructure, but the rest I can let go. That makes my work more manageable.
Why does that matter to you personally?
My father was a tile setter. He sometimes worked weekends. He once told me he regretted not spending more time with us when we were kids. I never felt like I missed anything growing up, but I don't want to end up with that same feeling toward Hannah. That's one chance you get. I want to be there. With 2.0, I hope I can finally work four days instead of five, and spend more time with our little one.
What stays?
I'm still a Google Developer Expert, and I still work on the tracking snippet and webperformance consultation. That's frontend, and frontend is where my passion is. I'll keep doing talks when the time is right. And I'll stay involved in the origin trials with Google Chrome. Those collaborations are what got us on stage at Google I/O two years in a row. For a small company from the north of the Netherlands, that still feels pretty special.
Erwin isn't the founder who shouts from the rooftops. But without him, there's no RUMvision. He built it, carried it, and now he gets to let some of it go.
Spot him at a conference. He's the one with the hat.
