I make websites fast. Permanently.
Companies call me after the standard recommendations didn't work. I diagnose the real architecture problems, ship the fixes with your engineering team, and set up monitoring so performance never regresses. My clients include Adevinta, Nestlé, eBay, Harvard, DPG Media, and Zalando.
Trusted by market leaders
Good agencies apply best practices. I engineer performance.
Most PageSpeed advice stops at Lighthouse suggestions. I go further: browser rendering pipelines, LoAF API attribution, Speculation Rules for instant navigations, third party governance at scale, architectural bottlenecks that only surface under real traffic. My process runs on field data from real users, not synthetic lab scores.
I measure before I touch anything
I deploy CoreDash, my own Real User Monitoring tool, to capture exactly what your visitors experience. Segmented by device, geography, and page type. Not averages. Actual sessions.
I ship the fixes, not a PDF
Most consultants hand you a report and disappear. I join your engineering team, implement the architectural changes myself, and make sure everything holds in production.
Your team owns it when I leave
Performance budgets in your CI/CD pipeline. Training for your engineers. CoreDash monitoring running 24/7. No ongoing dependency on me unless you want it.
Loop Earplugs
"Mobile load time down 800ms. 7% lift in checkout conversion. The ROI justified the investment immediately."
VP Engineering, Loop
Results
15 marketplaces. Third party governance at scale.
Reorganized the third party loading strategy across all Adevinta properties. 45% reduction in main thread blocking time. Ad revenue maintained.
60 minutes. Root cause identified.
A single diagnostic session uncovered what their team had missed for months. Blueprint delivered same day. Results measured within the week.
Ongoing performance partner
Their clients benefit from performance engineering that goes far beyond what a typical agency can deliver in house. Continuous collaboration across their portfolio.
Client Success
Don't just take my word for it
VP Product, Expedia Group
"We had 80+ third-party scripts and were failing CWV on every major property. Arjen got us passing without touching our ad revenue."
Head of Engineering, Swift
"Layout shift on checkout eliminated entirely. Went from 0.4 to 0.02 CLS across mobile and desktop."
VP Engineering, Loop
"Mobile load time down 800ms. 7% lift in checkout conversion. The ROI justified the investment immediately."
CTO, DPG Media
"He found bottlenecks in our component library that we'd missed for two years. Performance gains were visible within days."
VP Engineering, People Inc
"Seven brands, seven different stacks. Every single one got faster. No compromises on what makes each property unique."
Head of Digital, Rituals
"We used to break performance every other sprint. He set up budgets in our pipeline. Haven't had a regression since."
Product Lead, Miro
"Our dashboards were choking on main-thread work. 25% reduction in CPU usage. Users noticed immediately."
Engineering Manager, Zalando
"Every other audit we've had gave us a list of problems. This one told us exactly what to fix first and why."
Head of Platform, Adevinta
"45% reduction in blocking time across 15 marketplaces. And we didn't lose a single ad placement."
Lead Developer, Alza
"Transferred knowledge to our engineering team. We can now diagnose and resolve performance issues independently."
Why I built my own monitoring tool
CoreDash: Real User Monitoring built by a consultant, not a corporation
I wasn't impressed with the existing Core Web Vitals tracking tools. Either they were overpriced, or they lacked precision. So I built CoreDash. It is the RUM tool I use on every client engagement and it is the only one I trust for the level of detail my work requires.
EU only data storage. No cookies. No PII. No IP addresses. No consent banner required. GDPR compliance without compromise.
Real time field data
Not 28 day delayed CrUX averages. Actual sessions. Right now.
EU only. Zero PII.
Data stays in Europe. No consent banner needed. Full GDPR compliance.
Used on every client engagement
Full RUM tracking. No artificial URL limits. No data retention caps.
Find out what slow is costing you
I get more performance requests than I can take on. I do not take on every client. But if your site has a complex performance problem that your team has not been able to solve, I want to hear about it.
A 20 minute call. No pitch. We look at your real data, I identify the specific bottlenecks, and I tell you honestly what it would take to fix them.
Honest assessment
What is actually wrong and what it will take to fix it.
Feasibility confirmed
What results to expect and in what timeframe.
No commitment
The worst outcome is you leave with free insights you can use today.