diff --git a/config/config.exs b/config/config.exs
index bf1d637..4f11b4a 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -8,7 +8,7 @@ import Config
 config :mailgun_logger,
   ecto_repos: [MailgunLogger.Repo],
   env: Mix.env(),
-  store_messages: System.get_env("ML_STORE_MESSAGES") || false,
+  store_messages: System.get_env("ML_STORE_MESSAGES", "false") |> String.downcase() == "true",
   page_size: String.to_integer(System.get_env("ML_PAGESIZE", "50"))
 
 # Configures the endpoint
diff --git a/config/runtime.exs b/config/runtime.exs
index 0724a63..662f03e 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -1,5 +1,8 @@
 import Config
 
+config :mailgun_logger,
+  store_messages: System.get_env("ML_STORE_MESSAGES", "false") |> String.downcase() == "true"
+
 config :mailgun_logger, MailgunLoggerWeb.Endpoint,
   server: true,
   secret_key_base: System.get_env("SECRET_KEY_BASE")