Maputnik is a free and open source visual editor for the Mapbox GL style specification. You can either use the online version of Maputnik at http://editor.openmaptiles.org or download the editor to use it locally.
Edit the Style online
The easiest way to get started is choosing an existing style as a starting point. On http://editor.openmaptiles.org you can choose from many existing styles that work well with OpenMapTiles and directly edit them.
Once you are done editing the style you can download the modified style in JSON format.
Edit the Style locally
In our example, we will use the Positron style. Clone the repository containing the style JSON file using following command:
git clone https://github.com/openmaptiles/positron-gl-style.git
Now start Maputnik and tell the programm to watch the
style.json file for changes. Any time you change something in Maputnik, it will also save the changes to the
style.json file. You can even manually edit the
style.json file in your favorite text editor and then reload Maputnik to see the result.
To start with edit, run Maputnik and visit
http://localhost:8000 in your browser to access the editor.
maputnik --watch --file style.json
Check out the video tutorial how to use Maputnik to edit a local style.