diff --git a/config/application.rb b/config/application.rb
index ef38132e..15e3d59d 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -44,7 +44,7 @@ class Application < Rails::Application
     # notify mailer
     config.action_mailer.delivery_method = :notify
     config.action_mailer.notify_settings = {
-      api_key: ENV.fetch("GOVUK_NOTIFY_API_KEY"),
+      api_key: ENV.fetch("GOVUK_NOTIFY_API_KEY", "non_prod"),
     }
 
     config.x.govuk_notify.generic_email_template_id = ENV.fetch("GOVUK_NOTIFY_GENERIC_EMAIL_TEMPLATE_ID")