We get it, you’re a perfectionist. You want to filter out specific data, or certain labels. You want to style sizes and colors by fields. You want to customize polygon stroke colors, or configure whether features should be clickable.

Don’t worry, you’ve come to the right place.


Using the Advanced Editor

To open the advanced editor for any layer: click on the layer’s overflow menu (three dots) and select the Actions > Edit styles option.



Once opened, you’ll see a panel open on the right-hand side of the screen. This panel contains the Felt Style Language for the selected layer.


Modifying the Felt Style Language

The Felt Style Language (FSL) is a JSON-based specification of Felt styles, and is the single source of truth for a layer’s style. You can check this yourself by making changes in the Style Editor while having the Advanced Style Editor open:


Learn more about the Felt Style Language in our Developer Docs.