diff --git a/src/kvstore.rs b/src/kvstore.rs
index 094a46d..ea4a296 100644
--- a/src/kvstore.rs
+++ b/src/kvstore.rs
@@ -9,38 +9,39 @@ pub struct KvElement {
     pub updated_at: DateTime<Utc>,
     pub expire_at: DateTime<Utc>,
     pub update_count: i32,
-    pub locked: bool
+    pub locked: bool,
 }
 
 pub struct KvStore {
-    container: CHashMap<String, KvElement>
+    container: CHashMap<String, KvElement>,
 }
 
-impl KvStore
-{
-    pub fn new() -> KvStore
-    {
+impl KvStore {
+    pub fn new() -> KvStore {
         // TODO: prepare looped persistence
         KvStore {
-            container: CHashMap::new()
+            container: CHashMap::new(),
         }
     }
 
     pub fn set(&self, key: String, value: Vec<u8>) -> Option<KvElement> {
         // TODO: prepare iterative persistence
-        let mime_type = tree_magic::from_u8(value.as_ref());
         match &mut self.container.get_mut(&key) {
             Some(kv_element) => {
-                kv_element.data = value;
-                kv_element.mime_type = mime_type;
+                if !kv_element.locked {
+                    let mime_type = tree_magic::from_u8(value.as_ref());
+                    kv_element.data = value;
+                    kv_element.mime_type = mime_type;
+                }
                 kv_element.updated_at = Utc::now();
-                kv_element.update_count = kv_element.update_count + 1; 
+                kv_element.update_count = kv_element.update_count + 1;
                 Some(kv_element.to_owned())
-            },
+            }
             None => {
+                let mime_type = tree_magic::from_u8(value.as_ref());
                 let kv_element = KvElement {
                     data: value,
-                    mime_type: mime_type,
+                    mime_type,
                     created_at: Utc::now(),
                     updated_at: Utc::now(),
                     expire_at: Utc::now(),
@@ -55,7 +56,7 @@ impl KvStore
     pub fn get(&self, key: String) -> Option<KvElement> {
         match self.container.get(&key) {
             Some(value) => Some(value.clone()),
-            None => None
+            None => None,
         }
     }
 
@@ -64,8 +65,26 @@ impl KvStore
             Some(kv_element) => {
                 kv_element.locked = to_lock;
                 true
-            },
-            None => false
+            }
+            None => false,
+        }
+    }
+
+    pub fn increment_or_decrement(&self, key: String, value: f64) -> bool {
+        match &mut self.container.get_mut(&key) {
+            Some(kv_element) => {
+                let byte_to_string = String::from_utf8(kv_element.clone().data).unwrap(); // TODO: handle convert to string error
+                match byte_to_string.trim().parse::<f64>() {
+                    Ok(initial_value) => {
+                        kv_element.data = (initial_value + value).to_string().into_bytes();
+                        kv_element.updated_at = Utc::now();
+                        kv_element.update_count = kv_element.update_count + 1;
+                        true
+                    }
+                    Err(_) => false,
+                }
+            }
+            None => false,
         }
     }
 
@@ -74,4 +93,4 @@ impl KvStore
     pub fn drop(&self, key: String) {
         self.container.remove(&key);
     }
-}
\ No newline at end of file
+}
diff --git a/src/server.rs b/src/server.rs
index a9bcea5..20c8561 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -119,8 +119,14 @@ impl Server {
                 std::process::id()
             );
             info!("Lucid API Endpoint: https://{}/api/", bind_endpoint);
-            info!("SSL Certificate: {}", &configuration.general.ssl_certificate);
-            info!("SSL Private Key: {}", &configuration.general.ssl_certificate_key);
+            info!(
+                "SSL Certificate: {}",
+                &configuration.general.ssl_certificate
+            );
+            info!(
+                "SSL Private Key: {}",
+                &configuration.general.ssl_certificate_key
+            );
             info!("Use Ctrl+C to stop the server.");
             instance
                 .tls()
@@ -219,11 +225,30 @@ async fn patch_key(
     patch_value: PatchValue,
 ) -> Result<impl Reply, Rejection> {
     if let Some(_) = store.get(key.clone()) {
-        match patch_value.operation.as_str() {
-            "lock" | "unlock" => {
-                let r = store.switch_lock(key.to_string(), true);
-                println!("{}", r);
-                Ok("")
+        match patch_value.operation.to_lowercase().as_str() {
+            "lock" => {
+                store.switch_lock(key.to_string(), true);
+                Ok(warp::reply::json(&JsonMessage {
+                    message: "The specified key was successfully locked.".to_string(),
+                }))
+            }
+            "unlock" => {
+                store.switch_lock(key.to_string(), false);
+                Ok(warp::reply::json(&JsonMessage {
+                    message: "The specified key was successfully unlocked.".to_string(),
+                }))
+            }
+            "increment" => {
+                store.increment_or_decrement(key.to_string(), 1.0);
+                Ok(warp::reply::json(&JsonMessage {
+                    message: "The specified key was successfully incremented.".to_string(),
+                }))
+            }
+            "decrement" => {
+                store.increment_or_decrement(key.to_string(), -1.0);
+                Ok(warp::reply::json(&JsonMessage {
+                    message: "The specified key was successfully decremented.".to_string(),
+                }))
             }
             _ => Err(reject::custom(Error::InvalidOperation {
                 operation: patch_value.operation,