diff --git a/R/get_stac_data.R b/R/get_stac_data.R
index 9a04da2..c0f27ea 100644
--- a/R/get_stac_data.R
+++ b/R/get_stac_data.R
@@ -242,7 +242,7 @@ get_stac_data <- function(aoi,
     gdalwarp_options = character()
   )
 
-  if (is.null(sign_function) && stac_source == "https://planetarycomputer.microsoft.com/api/stac/v1") {
+  if (is.null(sign_function) && is_pc(stac_source)) {
     sign_function <- sign_planetary_computer
   }
 
@@ -962,3 +962,7 @@ figure_out_progress_length <- function(items_urls, mask_band, composite_function
   }
   length_progress
 }
+
+is_pc <- function(url) {
+  grepl("planetarycomputer.microsoft.com/api/stac/v1", url)
+}