diff --git a/src/main.rs b/src/main.rs
index c9e9abc..ff58da3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,79 +1,9 @@
-use std::collections::HashMap;
-use std::time::{Duration, Instant};
+use std::{collections::HashMap, time::Duration};
 
-struct NotificationService {
-    rate_limits: HashMap<String, RateLimit>,
-}
-
-struct RateLimit {
-    max_requests: u32,
-    per_duration: Duration,
-    recipient_counters: HashMap<String, RecipientCounter>,
-}
-
-struct RecipientCounter {
-    allowed_requests: u32,
-    last_request: Option<Instant>,
-}
-
-impl NotificationService {
-    fn new() -> Self {
-        NotificationService {
-            rate_limits: HashMap::new(),
-        }
-    }
-
-    fn send(
-        &mut self,
-        notification_type: &str,
-        recipient: &str,
-        message: &str,
-    ) -> Result<(), String> {
-        let rate_limit = self
-            .rate_limits
-            .entry(notification_type.to_string())
-            .or_insert(RateLimit {
-                max_requests: u32::MAX,
-                per_duration: Duration::from_secs(1),
-                recipient_counters: HashMap::new(),
-            });
-
-        let recipient_counter = rate_limit
-            .recipient_counters
-            .entry(recipient.to_string())
-            .or_insert(RecipientCounter {
-                allowed_requests: rate_limit.max_requests,
-                last_request: Some(Instant::now()),
-            });
-
-        let now = Instant::now();
-        let elapsed = now.duration_since(recipient_counter.last_request.unwrap_or(now));
-
-        if elapsed <= rate_limit.per_duration {
-            if recipient_counter.allowed_requests <= 0 {
-                return Err(format!(
-                    "Rate limit exceeded for {} notifications to {}. No more requests allowed.",
-                    notification_type, recipient
-                ));
-            }
-            recipient_counter.allowed_requests -= 1;
-        } else {
-            recipient_counter.last_request = Some(now);
-            recipient_counter.allowed_requests = rate_limit.max_requests - 1;
-        }
-
-        // Perform the actual notification sending here.
-        println!(
-            "Sending {} notification to {}: {}",
-            notification_type, recipient, message
-        );
-
-        Ok(())
-    }
-}
+mod notification_service;
 
 fn main() {
-    let mut service = NotificationService::new();
+    let mut service = notification_service::NotificationService::new();
 
     // Define rate limits for different notification types
     let rate_limits = vec![
@@ -85,7 +15,7 @@ fn main() {
     for (notification_type, max_requests, per_duration) in rate_limits {
         service.rate_limits.insert(
             notification_type.to_string(),
-            RateLimit {
+            notification_service::RateLimit {
                 max_requests,
                 per_duration,
                 recipient_counters: HashMap::new(),
diff --git a/src/notification_service.rs b/src/notification_service.rs
new file mode 100644
index 0000000..8ad0ca3
--- /dev/null
+++ b/src/notification_service.rs
@@ -0,0 +1,73 @@
+use std::collections::HashMap;
+use std::time::{Duration, Instant};
+
+pub struct NotificationService {
+    pub rate_limits: HashMap<String, RateLimit>,
+}
+
+pub struct RateLimit {
+    pub max_requests: u32,
+    pub per_duration: Duration,
+    pub recipient_counters: HashMap<String, RecipientCounter>,
+}
+
+pub struct RecipientCounter {
+    allowed_requests: u32,
+    last_request: Option<Instant>,
+}
+
+impl NotificationService {
+    pub fn new() -> Self {
+        NotificationService {
+            rate_limits: HashMap::new(),
+        }
+    }
+
+    pub fn send(
+        &mut self,
+        notification_type: &str,
+        recipient: &str,
+        message: &str,
+    ) -> Result<(), String> {
+        let rate_limit = self
+            .rate_limits
+            .entry(notification_type.to_string())
+            .or_insert(RateLimit {
+                max_requests: u32::MAX,
+                per_duration: Duration::from_secs(1),
+                recipient_counters: HashMap::new(),
+            });
+
+        let recipient_counter = rate_limit
+            .recipient_counters
+            .entry(recipient.to_string())
+            .or_insert(RecipientCounter {
+                allowed_requests: rate_limit.max_requests,
+                last_request: Some(Instant::now()),
+            });
+
+        let now = Instant::now();
+        let elapsed = now.duration_since(recipient_counter.last_request.unwrap_or(now));
+
+        if elapsed <= rate_limit.per_duration {
+            if recipient_counter.allowed_requests <= 0 {
+                return Err(format!(
+                    "Rate limit exceeded for {} notifications to {}. No more requests allowed.",
+                    notification_type, recipient
+                ));
+            }
+            recipient_counter.allowed_requests -= 1;
+        } else {
+            recipient_counter.last_request = Some(now);
+            recipient_counter.allowed_requests = rate_limit.max_requests - 1;
+        }
+
+        // Perform the actual notification sending here.
+        println!(
+            "Sending {} notification to {}: {}",
+            notification_type, recipient, message
+        );
+
+        Ok(())
+    }
+}