diff --git a/app/config.py b/app/config.py
index ced6a1f..0476c48 100644
--- a/app/config.py
+++ b/app/config.py
@@ -33,6 +33,7 @@ class Config:
     # Plaid (sandbox / development / production)
     PLAID_CLIENT_ID = os.environ.get('PLAID_CLIENT_ID', '')
     PLAID_SECRET    = os.environ.get('PLAID_SECRET', '')
+    # Valid values: sandbox, production (Plaid retired the 'development' environment)
     PLAID_ENV       = os.environ.get('PLAID_ENV', 'sandbox')
 
     # Schwab Developer API (OAuth 2.0)
diff --git a/app/services/plaid_service.py b/app/services/plaid_service.py
index 19caa44..a4eefb0 100644
--- a/app/services/plaid_service.py
+++ b/app/services/plaid_service.py
@@ -25,9 +25,10 @@ from flask import current_app
 log = logging.getLogger(__name__)
 
 PLAID_HOSTS = {
-    'sandbox':     'https://sandbox.plaid.com',
-    'development': 'https://development.plaid.com',
-    'production':  'https://production.plaid.com',
+    'sandbox':    'https://sandbox.plaid.com',
+    'production': 'https://production.plaid.com',
+    # 'development' was sunset by Plaid — map it to production so old configs don't break
+    'development': 'https://production.plaid.com',
 }
 
 # Plaid top-level category → PFM category name