diff --git a/spotify_to_ytmusic/spotify.py b/spotify_to_ytmusic/spotify.py
index 100705b..9377da7 100644
--- a/spotify_to_ytmusic/spotify.py
+++ b/spotify_to_ytmusic/spotify.py
@@ -1,4 +1,5 @@
 import html
+import string
 from urllib.parse import urlparse
 
 import spotipy
@@ -11,8 +12,18 @@ class Spotify:
     def __init__(self):
         settings = Settings()
         conf = settings["spotify"]
+        client_id = conf["client_id"]
+
+        assert set(client_id).issubset(
+            string.hexdigits
+        ), f"Spotify client_id not set or invalid: {client_id}"
+        client_secret = conf["client_secret"]
+        assert set(client_secret).issubset(
+            string.hexdigits
+        ), f"Spotify client_secret not set or invalid: {client_secret}"
+
         client_credentials_manager = SpotifyClientCredentials(
-            client_id=conf["client_id"], client_secret=conf["client_secret"]
+            client_id=client_id, client_secret=client_secret
         )
         self.api = spotipy.Spotify(client_credentials_manager=client_credentials_manager)
 
diff --git a/spotify_to_ytmusic/ytmusic.py b/spotify_to_ytmusic/ytmusic.py
index ebe579d..ccd6d5c 100644
--- a/spotify_to_ytmusic/ytmusic.py
+++ b/spotify_to_ytmusic/ytmusic.py
@@ -13,7 +13,9 @@
 class YTMusicTransfer:
     def __init__(self):
         settings = Settings()
-        self.api = YTMusic(settings["youtube"]["headers"], settings["youtube"]["user_id"])
+        headers = settings["youtube"]["headers"]
+        assert headers.startswith("{"), "ytmusicapi headers not set or invalid"
+        self.api = YTMusic(headers, settings["youtube"]["user_id"])
 
     def create_playlist(self, name, info, privacy="PRIVATE", tracks=None):
         return self.api.create_playlist(name, info, privacy, video_ids=tracks)