The Web Beyond the Edges of the Browser Window – Niels Leenheer | beyond tellerrand Düsseldorf 2026

Niels Leenheer has been sitting in the audience at beyond tellerrand for more than ten years. At Düsseldorf 2026 – the 15th edition – he took the stage himself. His talk is about obsessions: the good kind, where curiosity grabs you and you follow it into strange and wonderful places. For Niels, that has meant building a physics-simulated clock with breakable hands and a winding knob that snaps if you wind it too much. It has meant using the Web Audio API to draw SVG images on a 1980s oscilloscope – and then blowing that oscilloscope up, building his own simulator on a train, and eventually getting Doom running on the repaired scope. It has meant buying a flamethrower on AliExpress and controlling it with CSS. And it has meant CSS animations driving a laser projector, drawing SVGs in light on a darkened stage. Every single project was built with modern web standards. Every single one started as an obsession sparked by a talk he saw at a previous beyond tellerrand. All of them were, as Niels puts it, an absolute blast to create. This is one of the most joyful talks we have ever had on a beyond tellerrand stage. --- beyond tellerrand is an affordable, single-track event where creativity and technology meet. 🎟 Tickets and more: https://beyondtellerrand.com 📸 Photos from the event: https://beyondtellerrand.com/photos 🐘 Mastodon: https://mastodon.social/@btconf 💼 LinkedIn:   / beyondtellerrand   📸 Instagram:   / btconf   #btconf #webdevelopment #frontend #css #javascript #beyondtellerrand