diff --git a/docs/env-variables.md b/docs/env-variables.md
index 060444fc..4d14a117 100644
--- a/docs/env-variables.md
+++ b/docs/env-variables.md
@@ -15,7 +15,7 @@ This page outlines the environment variables used in the YamTrack project.
 | `IGDB_ID`       | IGDB API key for games. A default key is provided, but it's recommended to get your own as it has a low rate limit.                                                                                                                                   |
 | `IGDB_SECRET`   | IGDB API secret for games. A default value is provided, but it's recommended to get your own as it has a low rate limit.                                                                                                                              |
 | `IGDB_NSFW`     | Default to `False`. Set to `True` to include adult content in game searches.                                                                                                                                                                          |
-| `HARDCOVER_API` | Hardcover API key for books. A default key is provided, but it's recommended to get your own as it has a low rate limit.                                                                                                                              |
+| `HARDCOVER_API` | Hardcover API key for books. A default key is provided, but it's recommended to get your own as it has a low rate limit. Custom values must include the `Bearer ` prefix.                                                                              |
 | `COMICVINE_API` | ComicVine API key for comics. A default key is provided, but it's recommended to get your own as it has a low rate limit.                                                                                                                             |
 
 ## Media Import
diff --git a/src/config/settings.py b/src/config/settings.py
index 75eab9f6..389132a4 100644
--- a/src/config/settings.py
+++ b/src/config/settings.py
@@ -18,6 +18,7 @@ from decouple import (
     undefined,
 )
 from django.core.cache import CacheKeyWarning
+from django.core.exceptions import ImproperlyConfigured
 
 BASE_URL = config("BASE_URL", default=None)
 if BASE_URL:
@@ -424,6 +425,10 @@ HARDCOVER_API = config(
         "j4MVAEi_-w2N7DuiMgAxkfVc6RuKd88AHrOyzF5xLyU",
     ),
 )
+HARDCOVER_API = HARDCOVER_API.strip()
+if not HARDCOVER_API.startswith("Bearer "):
+    msg = "HARDCOVER_API must start with 'Bearer '."
+    raise ImproperlyConfigured(msg)
 
 COMICVINE_API = config(
     "COMICVINE_API",