diff --git a/src/configuration.rs b/src/configuration.rs
index 4f197dc..a496a3c 100644
--- a/src/configuration.rs
+++ b/src/configuration.rs
@@ -19,6 +19,12 @@ pub struct Settings {
 }
 
 #[derive(serde::Deserialize, Clone)]
+/// The email client settings.
+///
+/// * `base_url`: The base URL for the email client
+/// * `sender_email`: The email address of the sender
+/// * `authorization_token`: The authorization token
+/// * `timeout_milliseconds`: The timeout in milliseconds
 pub struct EmailClientSettings {
     pub base_url: String,
     pub sender_email: String,
@@ -31,6 +37,7 @@ pub struct EmailClientSettings {
 ///
 /// * `port`: The port to listen on
 /// * `host`: The host address to listen on
+/// * `base_url`: The base URL for the application
 pub struct ApplicationSettings {
     #[serde(deserialize_with = "deserialize_number_from_string")]
     pub port: u16,
diff --git a/src/routes/subscriptions_confirm.rs b/src/routes/subscriptions_confirm.rs
index ca5ed06..613ee13 100644
--- a/src/routes/subscriptions_confirm.rs
+++ b/src/routes/subscriptions_confirm.rs
@@ -12,12 +12,19 @@ pub struct Parameters {
     subscription_token: String,
 }
 
-// #[tracing::instrument(name = "Confirm a pending subscriber", skip(_parameters))]
+#[tracing::instrument(name = "Confirm a pending subscriber", skip(_parameters))]
+/// Confirm a pending subscriber.
+/// # Parameters
+/// - subscription_token: The subscription token.
+/// # Returns
+/// - 200 OK: The subscriber has been confirmed.
+/// - 400 Bad Request: The subscription token is missing.
 pub async fn confirm(Query(_parameters): Query<Parameters>) -> Response {
     println!("subscription_token: {}", _parameters.subscription_token);
     (StatusCode::OK,).into_response()
 }
 
+/// The routes for subscription confirmation.
 pub fn routes_subscriptions_confirm() -> Router<AppState> {
     Router::new().route("/subscriptions/confirm", get(confirm))
 }
diff --git a/src/startup.rs b/src/startup.rs
index 93397c0..dde2937 100644
--- a/src/startup.rs
+++ b/src/startup.rs
@@ -63,15 +63,13 @@ impl Application {
         );
         let listener = TcpListener::bind(&address).await?;
 
-        // FIXME: don't clone if not necessary
         let state = AppState {
-            db_pool: connection_pool.clone(),
-            email_client: email_client.clone(),
+            db_pool: connection_pool,
+            email_client,
             base_url: ApplicationBaseUrl(configuration.application.base_url),
         };
 
         let app = Router::new()
-            // TODO: check whether state cloning is what we want
             .merge(crate::routes::routes_subscriptions())
             .merge(crate::routes::routes_subscriptions_confirm())
             .with_state(state)