diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..8d3ae3c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+**target/
diff --git a/overwatch-rs/src/overwatch/handle.rs b/overwatch-rs/src/overwatch/handle.rs
index f4213ef..ee5dcae 100644
--- a/overwatch-rs/src/overwatch/handle.rs
+++ b/overwatch-rs/src/overwatch/handle.rs
@@ -34,7 +34,7 @@ impl OverwatchHandle {
     }
 
     /// Send a shutdown signal to the overwatch runner
-    pub async fn shutdown(&mut self) {
+    pub async fn shutdown(&self) {
         info!("Shutting down Overwatch");
         if let Err(e) = self
             .sender
@@ -48,7 +48,7 @@ impl OverwatchHandle {
     }
 
     /// Send a kill signal to the overwatch runner
-    pub async fn kill(&mut self) {
+    pub async fn kill(&self) {
         info!("Killing Overwatch");
         if let Err(e) = self
             .sender
@@ -63,14 +63,14 @@ impl OverwatchHandle {
 
     /// Send an overwatch command to the overwatch runner
     #[instrument(name = "overwatch-command-send", skip(self))]
-    pub async fn send(&mut self, command: OverwatchCommand) {
+    pub async fn send(&self, command: OverwatchCommand) {
         if let Err(e) = self.sender.send(command).await {
             error!(error=?e, "Error sending overwatch command");
         }
     }
 
     #[instrument(skip(self))]
-    pub async fn update_settings<S: Services>(&mut self, settings: S::Settings) {
+    pub async fn update_settings<S: Services>(&self, settings: S::Settings) {
         if let Err(e) = self
             .sender
             .send(OverwatchCommand::Settings(SettingsCommand(Box::new(
diff --git a/overwatch-rs/src/overwatch/mod.rs b/overwatch-rs/src/overwatch/mod.rs
index c416d0f..492a3ae 100644
--- a/overwatch-rs/src/overwatch/mod.rs
+++ b/overwatch-rs/src/overwatch/mod.rs
@@ -265,7 +265,7 @@ mod test {
     #[test]
     fn run_overwatch_then_stop() {
         let overwatch = OverwatchRunner::<EmptyServices>::run((), None);
-        let mut handle = overwatch.handle().clone();
+        let handle = overwatch.handle().clone();
 
         overwatch.spawn(async move {
             sleep(Duration::from_millis(500)).await;
@@ -278,7 +278,7 @@ mod test {
     #[test]
     fn run_overwatch_then_kill() {
         let overwatch = OverwatchRunner::<EmptyServices>::run((), None);
-        let mut handle = overwatch.handle().clone();
+        let handle = overwatch.handle().clone();
 
         overwatch.spawn(async move {
             sleep(Duration::from_millis(500)).await;
diff --git a/overwatch-rs/src/services/handle.rs b/overwatch-rs/src/services/handle.rs
index ab3e3cd..e490a30 100644
--- a/overwatch-rs/src/services/handle.rs
+++ b/overwatch-rs/src/services/handle.rs
@@ -1,5 +1,3 @@
-// std
-use std::marker::PhantomData;
 // crates
 use futures::future::{abortable, AbortHandle};
 use tokio::runtime::Handle;
@@ -25,7 +23,6 @@ pub struct ServiceHandle<S: ServiceCore> {
     overwatch_handle: OverwatchHandle,
     settings: SettingsUpdater<S::Settings>,
     initial_state: S::State,
-    _marker: PhantomData<S>,
 }
 
 /// Service core resources
@@ -58,7 +55,6 @@ impl<S: ServiceCore> ServiceHandle<S> {
             settings,
             initial_state,
             overwatch_handle,
-            _marker: PhantomData::default(),
         }
     }
 
diff --git a/overwatch-rs/src/services/relay.rs b/overwatch-rs/src/services/relay.rs
index 87fefd0..a23e94d 100644
--- a/overwatch-rs/src/services/relay.rs
+++ b/overwatch-rs/src/services/relay.rs
@@ -141,13 +141,13 @@ impl<S: ServiceCore> Relay<S> {
     }
 
     #[instrument(skip(self), err(Debug))]
-    pub async fn connect(&mut self) -> Result<OutboundRelay<S::Message>, RelayError> {
+    pub async fn connect(&self) -> Result<OutboundRelay<S::Message>, RelayError> {
         let (reply, receiver) = oneshot::channel();
         self.request_relay(reply).await;
         self.handle_relay_response(receiver).await
     }
 
-    async fn request_relay(&mut self, reply: oneshot::Sender<RelayResult>) {
+    async fn request_relay(&self, reply: oneshot::Sender<RelayResult>) {
         let relay_command = OverwatchCommand::Relay(RelayCommand {
             service_id: S::SERVICE_ID,
             reply_channel: ReplyChannel(reply),
@@ -157,7 +157,7 @@ impl<S: ServiceCore> Relay<S> {
 
     #[instrument(skip_all, err(Debug))]
     async fn handle_relay_response(
-        &mut self,
+        &self,
         receiver: oneshot::Receiver<RelayResult>,
     ) -> Result<OutboundRelay<S::Message>, RelayError> {
         let response = receiver.await;
diff --git a/overwatch-rs/src/services/settings.rs b/overwatch-rs/src/services/settings.rs
index 0cf6a85..0644ac0 100644
--- a/overwatch-rs/src/services/settings.rs
+++ b/overwatch-rs/src/services/settings.rs
@@ -22,7 +22,7 @@ impl<S: Clone> SettingsNotifier<S> {
     // of the method. Another option would be to spawn a task that updates a settings local value
     // each time an updated settings is received. This could not be so easy to do, since it will
     // need to hold a &mut to the holder (or needed to use a Cell/RefCell).
-    pub fn get_updated_settings(&mut self) -> S {
+    pub fn get_updated_settings(&self) -> S {
         self.notifier_channel.borrow().clone()
     }
 }
@@ -67,7 +67,7 @@ mod test {
     #[tokio::test]
     async fn settings_updater_sequence() {
         let updater = SettingsUpdater::new(10usize);
-        let mut notifier = updater.notifier();
+        let notifier = updater.notifier();
         let values = [10, 0usize];
         let mut seq = HashSet::from(values);
         let handle = tokio::spawn(timeout(Duration::from_secs(3), async move {
diff --git a/overwatch-rs/src/services/state.rs b/overwatch-rs/src/services/state.rs
index 5c9e7ab..385c151 100644
--- a/overwatch-rs/src/services/state.rs
+++ b/overwatch-rs/src/services/state.rs
@@ -127,7 +127,7 @@ impl<T> Clone for StateWatcher<T> {
 
 impl<S: ServiceState> StateUpdater<S> {
     /// Send a new state and notify the [`StateWatcher`]
-    pub fn update(&mut self, new_state: S) {
+    pub fn update(&self, new_state: S) {
         self.sender.send(new_state).unwrap_or_else(|_e| {
             error!("Error updating state");
         });
@@ -227,7 +227,7 @@ mod test {
     #[tokio::test]
     #[should_panic]
     async fn state_stream_collects() {
-        let (handle, mut updater): (
+        let (handle, updater): (
             StateHandle<UsizeCounter, PanicOnGreaterThanTen>,
             StateUpdater<UsizeCounter>,
         ) = StateHandle::new(
diff --git a/overwatch-rs/tests/print_service.rs b/overwatch-rs/tests/print_service.rs
index e21f1e2..3616241 100644
--- a/overwatch-rs/tests/print_service.rs
+++ b/overwatch-rs/tests/print_service.rs
@@ -86,8 +86,8 @@ struct TestApp {
 fn derive_print_service() {
     let settings: TestAppServiceSettings = TestAppServiceSettings { print_service: () };
     let overwatch = OverwatchRunner::<TestApp>::run(settings, None);
-    let mut handle = overwatch.handle().clone();
-    let mut print_service_relay = handle.relay::<PrintService>();
+    let handle = overwatch.handle().clone();
+    let print_service_relay = handle.relay::<PrintService>();
 
     overwatch.spawn(async move {
         let print_service_relay = print_service_relay
diff --git a/overwatch-rs/tests/settings_update.rs b/overwatch-rs/tests/settings_update.rs
index 6c195dd..209ed9f 100644
--- a/overwatch-rs/tests/settings_update.rs
+++ b/overwatch-rs/tests/settings_update.rs
@@ -35,11 +35,9 @@ impl ServiceCore for SettingsService {
 
     async fn run(mut self) {
         let Self {
-            state:
-                ServiceStateHandle {
-                    mut settings_reader,
-                    ..
-                },
+            state: ServiceStateHandle {
+                settings_reader, ..
+            },
         } = self;
 
         let print = async move {
@@ -72,7 +70,7 @@ fn settings_service_update_settings() {
     };
     let overwatch = OverwatchRunner::<TestApp>::run(settings.clone(), None);
     let handle = overwatch.handle().clone();
-    let mut handle2 = handle.clone();
+    let handle2 = handle.clone();
     settings.settings_service = "New settings".to_string();
     overwatch.spawn(async move { handle.clone().update_settings::<TestApp>(settings).await });
 
diff --git a/overwatch-rs/tests/state_handling.rs b/overwatch-rs/tests/state_handling.rs
index 26db4b1..0bb0e6c 100644
--- a/overwatch-rs/tests/state_handling.rs
+++ b/overwatch-rs/tests/state_handling.rs
@@ -69,9 +69,7 @@ impl ServiceCore for UpdateStateService {
 
     async fn run(mut self) {
         let Self {
-            state: ServiceStateHandle {
-                mut state_updater, ..
-            },
+            state: ServiceStateHandle { state_updater, .. },
         } = self;
         for value in 0..10 {
             state_updater.update(CounterState { value });
@@ -91,7 +89,7 @@ fn state_update_service() {
         update_state_service: (),
     };
     let overwatch = OverwatchRunner::<TestApp>::run(settings, None);
-    let mut handle = overwatch.handle().clone();
+    let handle = overwatch.handle().clone();
 
     overwatch.spawn(async move {
         sleep(Duration::from_secs(1)).await;