diff --git a/backend/src/domain/health.rs b/backend/src/domain/health.rs
index 897d83e..83891dc 100644
--- a/backend/src/domain/health.rs
+++ b/backend/src/domain/health.rs
@@ -106,12 +106,12 @@ impl HealthStatus {
     #[must_use]
     pub fn record_error(self) -> Self {
         match self {
-            Self::Healthy => Self::Degraded { consecutive_errors: 1 },
-            Self::Degraded { consecutive_errors } => {
-                Self::Degraded {
-                    consecutive_errors: consecutive_errors + 1,
-                }
-            }
+            Self::Healthy => Self::Degraded {
+                consecutive_errors: 1,
+            },
+            Self::Degraded { consecutive_errors } => Self::Degraded {
+                consecutive_errors: consecutive_errors + 1,
+            },
             Self::Unhealthy { reason } => Self::Unhealthy { reason },
         }
     }
@@ -161,7 +161,12 @@ mod tests {
         assert!(!status.is_healthy());
         assert!(status.is_degraded());
         assert!(!status.is_unhealthy());
-        assert_eq!(status, HealthStatus::Degraded { consecutive_errors: 3 });
+        assert_eq!(
+            status,
+            HealthStatus::Degraded {
+                consecutive_errors: 3
+            }
+        );
     }
 
     #[test]
@@ -183,7 +188,12 @@ mod tests {
         let status = HealthStatus::healthy();
         let status = status.record_error();
         assert!(status.is_degraded());
-        assert_eq!(status, HealthStatus::Degraded { consecutive_errors: 1 });
+        assert_eq!(
+            status,
+            HealthStatus::Degraded {
+                consecutive_errors: 1
+            }
+        );
     }
 
     #[test]
@@ -191,7 +201,12 @@ mod tests {
         let status = HealthStatus::degraded(2);
         let status = status.record_error();
         assert!(status.is_degraded());
-        assert_eq!(status, HealthStatus::Degraded { consecutive_errors: 3 });
+        assert_eq!(
+            status,
+            HealthStatus::Degraded {
+                consecutive_errors: 3
+            }
+        );
     }
 
     #[test]
@@ -274,15 +289,30 @@ mod tests {
         // Record first error -> Degraded with 1 error
         let status = status.record_error();
         assert!(status.is_degraded());
-        assert_eq!(status, HealthStatus::Degraded { consecutive_errors: 1 });
+        assert_eq!(
+            status,
+            HealthStatus::Degraded {
+                consecutive_errors: 1
+            }
+        );
 
         // Record second error -> Degraded with 2 errors
         let status = status.record_error();
-        assert_eq!(status, HealthStatus::Degraded { consecutive_errors: 2 });
+        assert_eq!(
+            status,
+            HealthStatus::Degraded {
+                consecutive_errors: 2
+            }
+        );
 
         // Record third error -> Degraded with 3 errors
         let status = status.record_error();
-        assert_eq!(status, HealthStatus::Degraded { consecutive_errors: 3 });
+        assert_eq!(
+            status,
+            HealthStatus::Degraded {
+                consecutive_errors: 3
+            }
+        );
 
         // Mark unhealthy -> Unhealthy
         let status = status.mark_unhealthy("Too many consecutive errors");
diff --git a/backend/src/domain/mod.rs b/backend/src/domain/mod.rs
index b8505ff..6f65b65 100644
--- a/backend/src/domain/mod.rs
+++ b/backend/src/domain/mod.rs
@@ -35,6 +35,6 @@
 //! - Type design: `specs/001-modbus-relay-control/types-design.md`
 //! - Domain specification: `specs/001-modbus-relay-control/spec.md`
 
-pub mod relay;
-pub mod modbus;
 pub mod health;
+pub mod modbus;
+pub mod relay;
diff --git a/backend/src/domain/relay/controler.rs b/backend/src/domain/relay/controller.rs
similarity index 100%
rename from backend/src/domain/relay/controler.rs
rename to backend/src/domain/relay/controller.rs
diff --git a/backend/src/domain/relay/entity.rs b/backend/src/domain/relay/entity.rs
index 00d52e0..265cfe8 100644
--- a/backend/src/domain/relay/entity.rs
+++ b/backend/src/domain/relay/entity.rs
@@ -54,7 +54,6 @@ impl Relay {
     pub fn label(&self) -> Option<RelayLabel> {
         self.label.clone()
     }
-
 }
 
 #[cfg(test)]
diff --git a/backend/src/domain/relay/mod.rs b/backend/src/domain/relay/mod.rs
index 26748e6..84ab6a3 100644
--- a/backend/src/domain/relay/mod.rs
+++ b/backend/src/domain/relay/mod.rs
@@ -3,11 +3,11 @@
 //! This module contains the core domain logic for relay control and management,
 //! including relay types, repository abstractions, and business rules.
 
+/// Controller error types for relay operations.
+pub mod controller;
+/// Relay entity representing the relay aggregate.
+pub mod entity;
 /// Repository trait and error types for relay persistence.
 pub mod repository;
 /// Domain types for relay identification and control.
 pub mod types;
-/// Controller error types for relay operations.
-pub mod controler;
-/// Relay entity representing the relay aggregate.
-pub mod entity;
diff --git a/backend/src/domain/relay/types/mod.rs b/backend/src/domain/relay/types/mod.rs
index e7ac867..573faa9 100644
--- a/backend/src/domain/relay/types/mod.rs
+++ b/backend/src/domain/relay/types/mod.rs
@@ -1,7 +1,7 @@
 mod relayid;
-mod relaystate;
 mod relaylabel;
+mod relaystate;
 
 pub use relayid::RelayId;
-pub use relaystate::RelayState;
 pub use relaylabel::RelayLabel;
+pub use relaystate::RelayState;
diff --git a/backend/src/domain/relay/types/relayid.rs b/backend/src/domain/relay/types/relayid.rs
index 9479543..d13fca6 100644
--- a/backend/src/domain/relay/types/relayid.rs
+++ b/backend/src/domain/relay/types/relayid.rs
@@ -1,4 +1,4 @@
-use crate::domain::relay::controler::ControllerError;
+use crate::domain::relay::controller::ControllerError;
 
 /// Unique identifier for a relay in the system.
 ///
@@ -33,7 +33,6 @@ impl RelayId {
     pub const fn as_u8(&self) -> u8 {
         self.0
     }
-
 }
 
 impl std::fmt::Display for RelayId {
diff --git a/backend/src/domain/relay/types/relaylabel.rs b/backend/src/domain/relay/types/relaylabel.rs
index 6ee06d9..425ad3e 100644
--- a/backend/src/domain/relay/types/relaylabel.rs
+++ b/backend/src/domain/relay/types/relaylabel.rs
@@ -1,5 +1,3 @@
-use std::fmt::Display;
-
 use thiserror::Error;
 
 /// Human-readable label for a relay.
@@ -15,7 +13,7 @@ pub enum RelayLabelError {
     #[error("Label cannot be empty")]
     Empty,
     #[error("Label exceeds maximum length of 50 characters: {0}")]
-    TooLong(usize)
+    TooLong(usize),
 }
 
 impl RelayLabel {