diff --git a/foodie_engagement_tweet.py b/foodie_engagement_tweet.py
index 2372e0b..0e3d6d1 100644
--- a/foodie_engagement_tweet.py
+++ b/foodie_engagement_tweet.py
@@ -126,7 +126,7 @@ def get_reference_date():
 
 def generate_engagement_tweet(author):
     """Generate an engagement tweet using author background themes."""
-    credentials = next((cred for cred in X_API_CREDENTIALS if cred["username"] == author["username"]), None)
+    credentials = X_API_CREDENTIALS.get(author["username"])
     if not credentials:
         logging.error(f"No X credentials found for {author['username']}")
         return None
diff --git a/foodie_utils.py b/foodie_utils.py
index a23d050..49dd207 100644
--- a/foodie_utils.py
+++ b/foodie_utils.py
@@ -216,7 +216,7 @@ def post_tweet(author, tweet, reply_to_id=None):
     import tweepy
     from datetime import datetime, timezone
 
-    credentials = next((cred for cred in X_API_CREDENTIALS if cred["username"] == author["username"]), None)
+    credentials = X_API_CREDENTIALS.get(author["username"])
     if not credentials:
         logging.error(f"No X credentials found for {author['username']}")
         return False
diff --git a/foodie_weekly_thread.py b/foodie_weekly_thread.py
index 374a11c..dfe41b1 100644
--- a/foodie_weekly_thread.py
+++ b/foodie_weekly_thread.py
@@ -100,7 +100,7 @@ def validate_twitter_credentials():
     logging.info("Validating Twitter API credentials for all authors")
     valid_credentials = []
     for author in AUTHORS:
-        credentials = next((cred for cred in X_API_CREDENTIALS if cred["username"] == author["username"]), None)
+        credentials = X_API_CREDENTIALS.get(author["username"])
         if not credentials:
             logging.error(f"No X credentials found for {author['username']} in X_API_CREDENTIALS")
             continue