cartoApiKey

API key for CARTO's basemap CDN, supplied by the host app. Used only when onlineBasemapProvider is CARTO_CDN.

CARTO enforce keys by WATERMARKING, not by rejecting: a keyless tile request still returns HTTP 200 with a valid PNG, but with the words "API KEY REQUIRED" rendered into the image. There is no status code, header or body-length signal to detect it by. An invalid key is byte-identical to no key at all, so a wrong value here fails silently and looks exactly like an unconfigured build.

Leave null/empty to send no key. That keeps the request byte-identical to the pre-key behaviour — a watermarked but SERVING basemap — rather than a blank one. A missing credential is a cosmetic regression; a hard failure would be an outage.

Changing this value invalidates the on-disk tile cache automatically (see BaseMapFragment#addCartoCdnRasterLayer), so a rotated key takes effect without any further change.