Independent JavaScript and Web Performance consultant
Teaching the next generation of ambitious developers.
Tech Speaker
I speak at tech conferences and private companies around the world about the Web.
Instructor
I taught full-stack development to 700+ students in Europe. Nowadays, I teach online for more than 100,000 students.
Trusted by
and other companies such as IKEA and MediaMarkt
Featured in
Awards
I'm humbled to be awarded for my continuous community engagements
Microsoft Most Valuable Professional
in Developer technologies (2019-2022)
Courses I've published
Gemini AI Web Video Course
Get started with the Google AI JS SDK by watching this free course.
Learn TypeScript
Learn TypeScript step by step in an interactive environment. Made for developers with JavaScript experience.
Learn HTML CSS
The easiest way to learn semantic and accessible HTML and CSS step by step.
Learn Programming
The easiest way to learn Programming concepts for absolute beginners step by step.
React Tutorial
The easiest way to learn React. Understand how React works not just how to build with React.
Learn JavaScript
Learn & practice modern JavaScript step by step with my interactive online course & flashcards.
Upcoming talks (2025)
Modern web performance patterns
How do you load a large library that is the core of your functionality? How do you achieve instant loading of a large web app? Get familiar with the modern patterns you can use to improve your web app's performance and make it stand out.
How z-index actually works: a deep dive into stacking order
How does the browser decide on the order of overlapping elements on the page? The stacking order has evolved over the years. Learn how it works and get recommendations for managing it in your project.
Interested in hosting one of these talks? Book me to speak at your conference in 2025.
Previous talks
Keynote: The (Abundant) State of the Web
Presented at FrontendFestival
Location: Nieuwegein, Netherlands
Date: June, 2025
View transitions: a deep dive
Presented at FDND x Fronteers meetup
Location: Hogeschool van Amsterdam, Netherlands
Date: May, 2024
View transitions: a deep dive
Presented at DevFest (Google Stockholm)
Location: Stockholm, Sweden
Date: December, 2023
Modern web performance patterns
Presented with Smashing Magazine
Location: online
Date: April, 2023
How z-index actually works: a deep dive into stacking order
Presented at Google Berlin
Location: Berlin, Germany
Date: Jan, 2023
Teaching programming: lessons learned
Presented at Google
Location: California, USA
Date: October, 2019
Speaking events
I’ve inspired audiences around the world. Book me to speak at your conference in 2025.
Products I've built
Learn TypeScript
Learn TypeScript step by step in an interactive environment. Made for developers with JavaScript experience.
JavaScript Projects (free)
Practice your web development skills by building the avatar designer and CurrencyPro projects.
JavaScript knowledge map
Discover and track the JavaScript concepts you need to learn.
Learn HTML CSS
The easiest way to learn semantic and accessible HTML and CSS step by step.
Learn Programming
The easiest way to learn Programming concepts for absolute beginners step by step.
React Tutorial
The easiest way to learn React. Understand how React works not just how to build with React.
Learn JavaScript
Learn & practice modern JavaScript step by step with this interactive online course.
Webdash
Webdash helps you visualize, monitor & manage your web project using community-driven plugins.
Code To Go
Code To Go helps you find up to date snippets for common JavaScript use cases.
Recent YouTube video
Articles I've published
Unlock exciting use cases with the Document Picture-in-Picture API
In this article, we explore the new Document Picture-in-Picture API and the use cases it unlocks.
chrome.com
Immutable array updates with Array.prototype.with
Learn how to use this new method to update an array without mutating the original array.
web.dev
JavaScript Fetch API use cases
Study notes and common use cases for the Fetch API in JavaScript.
learnjavascript.online
JavaScript .at() method – the complete guide.
The complete guide for String.at() and Array.at() in JavaScript. Learn additional use cases for the .at() method.
learnjavascript.online
JavaScript hasclass using classList.contains
Learn how to check if an element has a class or not using the modern alternative with classList.contains.
learnjavascript.online
Build A PWA With Webpack & Workbox
This tutorial will help you transform an app that doesn’t work offline into a PWA that works offline and shows an update available icon.
Smashing magazine
How to get more clients as a freelancer
Learn practical tips that will help you get more clients as a freelance developer while earning more. Kickstart your freelance career in 7 steps.
Freecodecamp
Running fetch in a web worker
An explainer for Web Workers and Comlink using fetch as an example Web API. Serves as an intro for Web workers.
Google Developer Experts
Impact on companies
Presented PWA Workshop at corporate event
Presented Progressive Web Apps workshop at a corporate event, showing off the company's dedication to supporting innovation.
Improved JavaScript performance by 20-fold
Invested minimal amount of work to optimize performance from 10 seconds of JavaScript processing, down to 0.4 seconds.
Improved web performance of a legacy web app
Improved loading time from 32 seconds to 4.5 seconds. Going from 6mb of JavaScript to 500kb with lazy loading.
Trained dev teams how to build performant PWAs
Presented the personalized PWA Workshop to multiple dev teams of different companies which greatly helped them build Performant PWAs for their clients.
Improved Performance & UX of a PWA
Improved Performance by more than 50% for a PWA targeting users in Africa. Also improved User Experience to offer a native look and feel.
Startup code review
Completed a detailed code review for a startup who has outsourced their development to an external team. Reported next actions based on security, performance & code quality.
Business offering
While most of my work revolves around building and writing courses for consumers, I am also available for some specific work with businesses.
In particular, you can book me to present a Web Performance workshop for your company.
Alternatively, you can hire me to fix your Web Performance issues.