Comment by bdon

Mapbox has been extremely generous in releasing their rendering libraries under a permissive license. Creating a map renderer that matches the user experience of Google Maps is a FAANG-level effort, and Mapbox GL also encompasses:

* A single style specification format that works well for both base map rendering and data overlays

* Parity across native and web rendering

* Smooth SDF text rendering with decent i18n support

* A font to SDF renderer that is open source: https://github.com/mapbox/node-fontnik

* A tiled data format that is open source: https://github.com/mapbox/vector-tile-spec

I hope this licensing change can spur some competition among open source renderers. I’d recommend taking a look at:

* Tangram: https://github.com/tangrams/tangram - another WebGL based renderer with some key advantages over MapboxGL JS such as custom shaders and canvas text

* OpenLayers: https://openlayers.org has some vector and WebGL capabilities now as well

* Harp: https://www.harp.gl is another new WebGL option

I've been working recently with Tangram, so contact me (see user link) if you have questions or are interested in collaborating!