Disclaimer: I'm the Leaflet author and I also work on Mapbox GL.

It's true that Mapbox currently focuses its efforts on GL, but they are not "moving away from Leaflet" — Leaflet will continue to be supported as one of the first-class clients to be used with Mapbox services (and GL-based styles have a raster tiles fallback). Leaflet is very mature, has a huge community, is suited for most simple mapping needs, is very easy to learn, and doesn't require a lot of development effort from the Mapbox side to support.

Mapbox GL on the other hand represents a vector rendering technology, which is very different. It is much more powerful than conventional raster tile based clients, and enables applications never seen before in the online mapping industry, but it's also many times heavier, more complex, and much harder to learn. Rendering vector data on the client is something Mapbox bets on as the future of mapping, but it's incredibly challenging to build, so it requires a lot of focus.

I'll continue to maintain both libraries — while they have some overlap, there's a place for both.

I love that I can ask a question like this here on HN and get an answer from the Leaflet author. Thanks for taking the time to respond.

Hope they continue to contribute to Leaflet, especially seen as Mourner is on the Mapbox team.

Looks like it. That's kinda lame. But I guess I understand why they're doing it.

Why are they doing this?

mapbox-gl-js focuses on vector tiles and webgl rendering. I'm not sure if it even supports raster tiles, canvas and other "legacy".

Looks like it does support raster tiles: https://www.mapbox.com/mapbox-gl-js/example/map-tiles/

You are right.

It came to me, that after all, they have to, if they want to display ortophoto or satellite tiles.

I was thinking more in the terms of street maps or thematic maps, where mapbox-gl-js displays them in a very nice way using vector tiles.

It does support raster tiles, using them in production here.

How would you say it is compared to leaflet? much more complex?

We chose it mostly because at the time, it looked like it had more active maintenance from the people at Mapbox, and it eventually looked like it was going to pass Leaflet.

I wouldn't say it's more complex. mapbox-gl favors a more declarative style (look into "Map Style" in the docs), but the concepts are not that different than Leaflet.

Web GL features (such as video support) is an obvious advantage, and part of why we chose it. We don't use plugins for this project, so can't say much about that.