Flightradar24: Live Flights Rendered in WebGL2, Updated Every Two Seconds

Open Flightradar24 in a browser and just sit there for a minute. Tens of thousands of little yellow aircraft icons crawl across a vector map of the planet, each one representing a real commercial flight updating its position every two to three seconds. Zoom into Heathrow and watch the orderly parade of dots lining up on approach. Click any icon and you get altitude, speed, heading, aircraft type, even a full 3D cockpit view built on CesiumJS with MapBox terrain.

The whole thing runs on WebGL2. From the base map tiles (vector, not raster, so zoom is continuous) to the aircraft icons and flight trails, everything is GPU-rendered in the browser. The 3D view layers in a Cesium globe with real terrain and satellite imagery, pulling 3D aircraft models sourced from the FlightGear community. Behind the pixels, a network of around 58,000 volunteer-operated ADS-B receivers feeds live transponder data into the system, supplemented by satellite coverage over oceans. The engineering team has essentially built one of the most data-dense real-time WebGL applications on the public internet. It is not a demo. It is not a proof of concept. It is a product used by millions of people, including pilots, during actual emergencies.

Flightradar24 was started in 2006 by two Swedish aviation geeks, Mikael Robertsson and Olov Lindberg, who stuck an antenna on a Stockholm rooftop because they were curious. Twenty years later, the company tracks over 160,000 flights a day across a globe rendered in your browser tab. Their GitHub has 14 repos including forks of Three.js and a Cesium terrain builder worth poking through. Read the engineering blog at flightradar24.com/blog for the occasional deep dive into how they keep all those little yellow dots moving without melting your GPU. Open DevTools, inspect the WebGL calls, and appreciate the scale of what's quietly happening in a single browser context.