SpaceX
I helped with the design and operation of SpaceX's Starlink satellite mega-constellation. Most of my time was spent building telemetry, real time simulation, and rendering software.
Mapbox
I worked at Mapbox for 5 years building open source cartography and navigation software.
Turf
Turf is a JavaScript library for spatial analysis. I started the project in 2013 looking for an efficient way to manipulate and visualize geographic data. The project has survived on the contributions from developers around the world.