Sander van Surksum | Web Performance Consultant
Sander van Surksum is a web performance consultant at Iron/Out, specialising in Core Web Vitals optimisation for enterprise e-commerce and SaaS companies. With years of hands-on experience improving Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS), Sander helps organisations translate performance metrics into measurable business results.
Sander works with development teams to identify bottlenecks in critical rendering paths, optimise resource delivery, and implement frontend observability strategies that ensure performance improvements are maintained long-term.
Expertise & Services
- Core Web Vitals audits – Identifying and prioritising performance bottlenecks in LCP, INP, and CLS
- LCP optimisation – Image delivery, resource prioritisation, and server response time improvements
- INP optimisation – JavaScript execution profiling and interaction responsiveness
- CLS remediation – Layout stability fixes across dynamic content and ad placements
- Frontend observability – Setting up RUM tooling and performance monitoring dashboards
- Performance culture – Training development teams on continuous performance practices
Why web performance matters
Web performance directly affects user experience, conversion rates, and search rankings. A 100ms improvement in page load time can increase conversions by 1–2%. Google's Core Web Vitals are a ranking signal, meaning poor performance visibility in search results.
Sander's approach combines technical depth with business context. Every optimisation is measured against its impact on real users and revenue.
Visit sandervansurksum.nl for more about Sander's work and writing on web performance.
Frequently asked questions
What does a web performance consultant do?
A web performance consultant helps organisations improve their website speed and user experience by optimising Core Web Vitals metrics like LCP, INP, and CLS. They conduct performance audits, identify bottlenecks, and implement solutions that improve page load times, leading to better conversion rates and search engine rankings.
How can a web performance specialist improve my site?
A web performance specialist analyses your website using real user monitoring data and lab tests to identify performance issues. They optimise images, reduce JavaScript execution time, improve server response times, eliminate layout shifts, and implement frontend observability to continuously monitor and maintain optimal performance.
What results can web performance optimisation deliver?
Results vary per site, but Iron/Out client work shows what is achievable: Simyo reduced mobile INP from 413ms to 150ms at the 75th percentile, Autoweek grew the share of URLs with a good LCP from 74% to 85%, and Frasers Group brands lifted UX Scores from 75 to 96 (SportsDirect), 79 to 98 (House of Fraser), and 80 to 99 (Flannels), measured over 3 million+ sessions.
What are Core Web Vitals?
Core Web Vitals are Google's metrics for measuring user experience: Largest Contentful Paint (LCP) measures loading speed, Interaction to Next Paint (INP) measures interactivity, and Cumulative Layout Shift (CLS) measures visual stability. These metrics directly impact search rankings and user satisfaction.
