diff --git a/01 Getting Started/app.rb b/01 Getting Started/app.rb
index b37c5e6..392604b 100644
--- a/01 Getting Started/app.rb	
+++ b/01 Getting Started/app.rb	
@@ -10,6 +10,9 @@ class GiftBasket < Sinatra::Base
   API_SECRET = ENV['API_SECRET']
   APP_URL = "jamie.ngrok.io"
 
+  fail 'API_KEY environment variable is not set' if API_KEY.blank?
+  fail 'API_SECRET environment variable is not set' if API_SECRET.blank?
+
   def initialize
     @tokens = {}
     super
diff --git a/02 Charging For Your App/app.rb b/02 Charging For Your App/app.rb
index c6fa6f5..73aa860 100644
--- a/02 Charging For Your App/app.rb	
+++ b/02 Charging For Your App/app.rb	
@@ -10,6 +10,9 @@ class GiftBasket < Sinatra::Base
   API_SECRET = ENV['API_SECRET']
   APP_URL = "jamie.ngrok.io"
 
+  fail 'API_KEY environment variable is not set' if API_KEY.blank?
+  fail 'API_SECRET environment variable is not set' if API_SECRET.blank?
+
   def initialize
     @tokens = {}
     super