A sequence of custom parameters appended to the URL of all requests related to a layer.
Referenced by: Annotation Layer (ArcGISAnnotationLayer), Catalog Layer (CatalogLayer), CSV Layer (CSV), Dimension Layer (ArcGISDimensionLayer), Feature Layer (ArcGISFeatureLayer), GeoJSON Layer (GeoJSON), Image Service Layer (ArcGISImageServiceLayer), Image Service Vector Layer (ArcGISImageServiceVectorLayer), Knowledge Graph Layer (KnowledgeGraphLayer), Link Chart Layer (LinkChartLayer), Map Service Layer (ArcGISMapServiceLayer), Oriented Imagery Layer (OrientedImageryLayer), Parquet Layer (ParquetLayer), Stream Layer (ArcGISStreamLayer), Subtype Group Layer (SubtypeGroupLayer), Subtype Group Table (SubtypeGroupTable), table, Tiled Image Service Layer (ArcGISTiledImageServiceLayer), Tiled Map Service Layer (ArcGISTiledMapServiceLayer), Vector Tile Layer (VectorTileLayer), Web Coverage Service Layer (WCS)
Example
FeatureLayer with custom parameters
{ "layerType": "ArcGISFeatureLayer", "url": "https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/Home_Value_and_Income/FeatureServer/5", "title": "Median Home Value and Income - Block Group", "customParameters": { "key": "7FA3B7BABB7B45749BF3C6358F2B228F" }}