diff --git a/.env.example b/.env.example
index a06013d..4b575e4 100644
--- a/.env.example
+++ b/.env.example
@@ -4,3 +4,6 @@ TRAKT_SLURM=
 
 # optional - only needed if using steam service
 STEAM_WEBAPI_KEY=
+
+# optional - only needed if using hardcover service
+HARDCOVER_API_KEY=