Felt supports custom map backgrounds via any web-based map service supporting the popular XYZ map tile format. Compatible map tiles can be created via Mapbox Studio, found on ArcGIS servers, purchased from Planet, or found freely online via providers like Stamen.
Where are some places to get a custom map background?
How to add a custom map background in Felt
To use custom map backgrounds, provide Felt with a tile URL template that includes the {z}, {x}, and {y} parts as-is with other parts like layer names or API tokens filled-in. Felt will automatically swap in the {z}=zoom, {x}=column, and {y}=row values as you pan and zoom around your map.
Look for the “Background +” button in the bottom-right corner of a Felt map:
Select “From URL” in the popup window, and enter a tile URL template like this example, http://tile.openstreetmap.org/{z}/{x}/{y}.png. Some providers, like OSM in this example, require user-visible attribution which you can add in the “Attribution” section:
Your tile URL template must include space for {z}=zoom, {x}=column, and {y}=row values like the example above. Many popular online map services make URLs available in this format.
Cached image services can be hosted via ArcGIS Online or on your own organization’s server. Access individual background image tiles via the Image Tile REST API:
https://{imageservice-url}/tile/**{z}/{y}/{x}**
Note that the order of {x} and {y} are switched in ArcGIS compared to other services here.
Image Tile-ArcGIS REST APIs | ArcGIS Developers
Sample tile URL templates
Use these directly in Felt:
https://services.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer/tile/**{z}/{y}/{x}**
https://services.arcgisonline.com/arcgis/rest/services/Canvas/World_Dark_Gray_Base/MapServer/tile/**{z}/{y}/{x}**
Tiles hosted by MapTiler can be used in Felt via Raster Tiles for Leaflet JS:
https://api.maptiler.com/maps/{layer}/{z}/{x}/{y}.png?key={key}