diff --git a/config/default.json b/config/default.json
index 06b4e3d..ff55504 100644
--- a/config/default.json
+++ b/config/default.json
@@ -19,7 +19,9 @@
       { "period": "5 minutes", "limit": 0 }
     ]
   },
-  "message_id_hmac_key": "YOU MUST CHANGE ME",
+  "messagedata": {
+      "hmackey": "YOU MUST CHANGE ME"
+  },
   "logging": "mozlog",
   "provider": "ses",
   "redis": {
diff --git a/src/message_data/mod.rs b/src/message_data/mod.rs
index 3a68352..6e30b18 100644
--- a/src/message_data/mod.rs
+++ b/src/message_data/mod.rs
@@ -28,7 +28,7 @@ impl MessageData {
             client: RedisClient::open(
                 format!("redis://{}:{}/", settings.redis.host, settings.redis.port).as_str(),
             ).expect("redis connection error"),
-            hmac_key: settings.message_id_hmac_key.clone(),
+            hmac_key: settings.messagedata.hmackey.clone(),
         }
     }
 
diff --git a/src/message_data/test.rs b/src/message_data/test.rs
index f1c7567..f4a6f08 100644
--- a/src/message_data/test.rs
+++ b/src/message_data/test.rs
@@ -63,7 +63,7 @@ impl TestFixture {
     pub fn setup(test: &str) -> TestFixture {
         let settings = Settings::new().expect("config error");
         let unhashed_key = format!("fxa-email-service.test.message-data.{}.{}", test, now());
-        let mut hmac = Hmac::<Sha256>::new_varkey(settings.message_id_hmac_key.as_bytes()).unwrap();
+        let mut hmac = Hmac::<Sha256>::new_varkey(settings.messagedata.hmackey.as_bytes()).unwrap();
         hmac.input(unhashed_key.as_bytes());
         let internal_key = format!("msg:{:x}", hmac.result().code());
         TestFixture {
diff --git a/src/settings/mod.rs b/src/settings/mod.rs
index 61f8e1f..3591d24 100644
--- a/src/settings/mod.rs
+++ b/src/settings/mod.rs
@@ -51,6 +51,11 @@ pub struct BounceLimits {
     pub soft: Vec<BounceLimit>,
 }
 
+#[derive(Debug, Default, Deserialize, Serialize)]
+pub struct MessageData {
+    pub hmackey: String,
+}
+
 #[derive(Debug, Default, Deserialize, Serialize)]
 pub struct Redis {
     #[serde(deserialize_with = "deserialize::host")]
@@ -93,7 +98,7 @@ pub struct Settings {
     pub authdb: AuthDb,
     pub aws: Aws,
     pub bouncelimits: BounceLimits,
-    pub message_id_hmac_key: String,
+    pub messagedata: MessageData,
     pub logging: String,
     #[serde(deserialize_with = "deserialize::provider")]
     pub provider: String,
@@ -136,7 +141,7 @@ impl Settings {
             Ok(settings) => {
                 if let Ok(rocket_env) = env::var("ROCKET_ENV") {
                     if rocket_env == "production"
-                        && &settings.message_id_hmac_key == "YOU MUST CHANGE ME"
+                        && &settings.messagedata.hmackey == "YOU MUST CHANGE ME"
                     {
                         panic!("Please set a valid HMAC key.")
                     }
diff --git a/src/settings/test.rs b/src/settings/test.rs
index f61663c..7082dd5 100644
--- a/src/settings/test.rs
+++ b/src/settings/test.rs
@@ -65,6 +65,7 @@ fn env_vars_take_precedence() {
         "FXA_EMAIL_AWS_SQSURLS_DELIVERY",
         "FXA_EMAIL_AWS_SQSURLS_NOTIFICATION",
         "FXA_EMAIL_BOUNCELIMITS_ENABLED",
+        "FXA_EMAIL_MESSAGEDATA_HMACKEY",
         "FXA_EMAIL_PROVIDER",
         "FXA_EMAIL_REDIS_HOST",
         "FXA_EMAIL_REDIS_PORT",
@@ -114,6 +115,7 @@ fn env_vars_take_precedence() {
                 }
             };
             let bounce_limits_enabled = !settings.bouncelimits.enabled;
+            let message_data_hmac_key = String::from("something else");
             let provider = if settings.provider == "ses" {
                 "sendgrid"
             } else {
@@ -142,6 +144,10 @@ fn env_vars_take_precedence() {
                 "FXA_EMAIL_BOUNCELIMITS_ENABLED",
                 &bounce_limits_enabled.to_string(),
             );
+            env::set_var(
+                "FXA_EMAIL_MESSAGEDATA_HMACKEY",
+                &message_data_hmac_key.to_string(),
+            );
             env::set_var("FXA_EMAIL_PROVIDER", &provider);
             env::set_var("FXA_EMAIL_REDIS_HOST", &redis_host);
             env::set_var("FXA_EMAIL_REDIS_PORT", &redis_port.to_string());
@@ -154,6 +160,7 @@ fn env_vars_take_precedence() {
                     assert_eq!(env_settings.authdb.baseuri, auth_db_base_uri);
                     assert_eq!(env_settings.aws.region, aws_region);
                     assert_eq!(env_settings.bouncelimits.enabled, bounce_limits_enabled);
+                    assert_eq!(env_settings.messagedata.hmackey, message_data_hmac_key);
                     assert_eq!(env_settings.provider, provider);
                     assert_eq!(env_settings.redis.host, redis_host);
                     assert_eq!(env_settings.redis.port, redis_port);