diff --git a/docs/api.js b/docs/api.js
index 5f887e94..eff63583 100644
--- a/docs/api.js
+++ b/docs/api.js
@@ -9,7 +9,7 @@ function generateExamples(endpoint, method, body = null) {
   }
 
   return {
-    cURL: `curl -u user:pass -X ${method.trim()} -k https://localhost:47990${endpoint.trim()}${curlBodyString}`,
+    cURL: `curl -u user:pass -H "Content-Type: application/json" -X ${method.trim()} -k https://localhost:47990${endpoint.trim()}${curlBodyString}`,
     Python: `import json
 import requests
 from requests.auth import HTTPBasicAuth
@@ -30,6 +30,7 @@ requests.${method.trim().toLowerCase()}(
 .then(data => console.log(data));`,
     PowerShell: `Invoke-RestMethod \`
   -SkipCertificateCheck \`
+  -ContentType 'application/json' \`
   -Uri 'https://localhost:47990${endpoint.trim()}' \`
   -Method ${method.trim()} \`
   -Headers @{Authorization = 'Basic ' + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes('user:pass'))}
diff --git a/src/confighttp.cpp b/src/confighttp.cpp
index 4ba09b88..43d6df24 100644
--- a/src/confighttp.cpp
+++ b/src/confighttp.cpp
@@ -213,6 +213,39 @@ namespace confighttp {
     response->write(code, tree.dump(), headers);
   }
 
+  /**
+   * @brief Validate the request content type and send bad request when mismatch.
+   * @param response The HTTP response object.
+   * @param request The HTTP request object.
+   * @param contentType The expected content type
+   */
+  bool check_content_type(resp_https_t response, req_https_t request, const std::string_view &contentType) {
+    auto requestContentType = request->header.find("content-type");
+    if (requestContentType == request->header.end()) {
+      bad_request(response, request, "Content type not provided");
+      return false;
+    }
+    // Extract the media type part before any parameters (e.g., charset)
+    std::string actualContentType = requestContentType->second;
+    size_t semicolonPos = actualContentType.find(';');
+    if (semicolonPos != std::string::npos) {
+      actualContentType = actualContentType.substr(0, semicolonPos);
+    }
+
+    // Trim whitespace and convert to lowercase for case-insensitive comparison
+    boost::algorithm::trim(actualContentType);
+    boost::algorithm::to_lower(actualContentType);
+
+    std::string expectedContentType(contentType);
+    boost::algorithm::to_lower(expectedContentType);
+
+    if (actualContentType != expectedContentType) {
+      bad_request(response, request, "Content type mismatch");
+      return false;
+    }
+    return true;
+  }
+
   /**
    * @brief Get the index page.
    * @param response The HTTP response object.
@@ -535,6 +568,9 @@ namespace confighttp {
    * @api_examples{/api/apps| POST| {"name":"Hello, World!","index":-1}}
    */
   void saveApp(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -602,6 +638,9 @@ namespace confighttp {
    * @api_examples{/api/apps/close| POST| null}
    */
   void closeApp(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -623,6 +662,9 @@ namespace confighttp {
    * @api_examples{/api/apps/9999| DELETE| null}
    */
   void deleteApp(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -703,6 +745,9 @@ namespace confighttp {
    * @api_examples{/api/unpair| POST| {"uuid":"1234"}}
    */
   void unpair(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -733,6 +778,9 @@ namespace confighttp {
    * @api_examples{/api/clients/unpair-all| POST| null}
    */
   void unpairAll(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -809,6 +857,9 @@ namespace confighttp {
    * @api_examples{/api/config| POST| {"key":"value"}}
    */
   void saveConfig(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -855,6 +906,9 @@ namespace confighttp {
    * @api_examples{/api/covers/upload| POST| {"key":"igdb_1234","url":"https://images.igdb.com/igdb/image/upload/t_cover_big_2x/abc123.png"}}
    */
   void uploadCover(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -938,6 +992,9 @@ namespace confighttp {
    * @api_examples{/api/password| POST| {"currentUsername":"admin","currentPassword":"admin","newUsername":"admin","newPassword":"admin","confirmNewPassword":"admin"}}
    */
   void savePassword(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!config::sunshine.username.empty() && !authenticate(response, request)) {
       return;
     }
@@ -1008,6 +1065,9 @@ namespace confighttp {
    * @api_examples{/api/pin| POST| {"pin":"1234","name":"My PC"}}
    */
   void savePin(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -1044,6 +1104,9 @@ namespace confighttp {
    * @api_examples{/api/reset-display-device-persistence| POST| null}
    */
   void resetDisplayDevicePersistence(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
@@ -1063,6 +1126,9 @@ namespace confighttp {
    * @api_examples{/api/restart| POST| null}
    */
   void restart(resp_https_t response, req_https_t request) {
+    if (!check_content_type(response, request, "application/json")) {
+      return;
+    }
     if (!authenticate(response, request)) {
       return;
     }
diff --git a/src_assets/common/assets/web/apps.html b/src_assets/common/assets/web/apps.html
index 66e264e3..8b0cb517 100644
--- a/src_assets/common/assets/web/apps.html
+++ b/src_assets/common/assets/web/apps.html
@@ -440,7 +440,12 @@
           "Are you sure to delete " + this.apps[id].name + "?"
         );
         if (resp) {
-          fetch("./api/apps/" + id, { method: "DELETE" }).then((r) => {
+          fetch("./api/apps/" + id, {
+            method: "DELETE",
+            headers: { 
+              "Content-Type": "application/json" 
+            },
+          }).then((r) => {
             if (r.status === 200) document.location.reload();
           });
         }
@@ -540,6 +545,9 @@
         this.coverFinderBusy = true;
         fetch("./api/covers/upload", {
           method: "POST",
+          headers: {
+            'Content-Type': 'application/json'
+          },
           body: JSON.stringify({
             key: cover.key,
             url: cover.saveUrl,
@@ -555,6 +563,9 @@
         this.editForm["image-path"] = this.editForm["image-path"].toString().replace(/"/g, '');
         fetch("./api/apps", {
           method: "POST",
+          headers: {
+            'Content-Type': 'application/json'
+          },
           body: JSON.stringify(this.editForm),
         }).then((r) => {
           if (r.status === 200) document.location.reload();
diff --git a/src_assets/common/assets/web/config.html b/src_assets/common/assets/web/config.html
index e6a85b87..f021fd71 100644
--- a/src_assets/common/assets/web/config.html
+++ b/src_assets/common/assets/web/config.html
@@ -371,6 +371,9 @@
 
         return fetch("./api/config", {
           method: "POST",
+          headers: {
+            'Content-Type': 'application/json'
+          },
           body: JSON.stringify(config),
         }).then((r) => {
           if (r.status === 200) {
@@ -393,7 +396,10 @@
               this.saved = this.restarted = false;
             }, 5000);
             fetch("./api/restart", {
-              method: "POST"
+              method: "POST",
+              headers: {
+                "Content-Type": "application/json"
+              }
             });
           }
         });
diff --git a/src_assets/common/assets/web/password.html b/src_assets/common/assets/web/password.html
index 854ee596..9f1e7194 100644
--- a/src_assets/common/assets/web/password.html
+++ b/src_assets/common/assets/web/password.html
@@ -92,6 +92,9 @@
         this.error = null;
         fetch("./api/password", {
           method: "POST",
+          headers: {
+            'Content-Type': 'application/json'
+          },
           body: JSON.stringify(this.passwordData),
         }).then((r) => {
           if (r.status === 200) {
diff --git a/src_assets/common/assets/web/pin.html b/src_assets/common/assets/web/pin.html
index a5dcdb5d..d16a5de1 100644
--- a/src_assets/common/assets/web/pin.html
+++ b/src_assets/common/assets/web/pin.html
@@ -39,7 +39,13 @@
         let name = document.querySelector("#name-input").value;
         document.querySelector("#status").innerHTML = "";
         let b = JSON.stringify({pin: pin, name: name});
-        fetch("./api/pin", {method: "POST", body: b})
+        fetch("./api/pin", {
+          method: "POST", 
+          headers: {
+            'Content-Type': 'application/json'
+          }, 
+          body: b
+        })
           .then((response) => response.json())
           .then((response) => {
             if (response.status === true) {
diff --git a/src_assets/common/assets/web/troubleshooting.html b/src_assets/common/assets/web/troubleshooting.html
index 46d7218b..d742867f 100644
--- a/src_assets/common/assets/web/troubleshooting.html
+++ b/src_assets/common/assets/web/troubleshooting.html
@@ -207,7 +207,11 @@
         },
         closeApp() {
           this.closeAppPressed = true;
-          fetch("./api/apps/close", { method: "POST" })
+          fetch("./api/apps/close", { 
+            method: "POST",
+            headers: {
+                "Content-Type": "application/json"
+            } })
             .then((r) => r.json())
             .then((r) => {
               this.closeAppPressed = false;
@@ -219,7 +223,12 @@
         },
         unpairAll() {
           this.unpairAllPressed = true;
-          fetch("./api/clients/unpair-all", { method: "POST" })
+          fetch("./api/clients/unpair-all", { 
+            method: "POST",
+            headers: {
+                "Content-Type": "application/json"
+            }
+           })
             .then((r) => r.json())
             .then((r) => {
               this.unpairAllPressed = false;
@@ -231,7 +240,13 @@
             });
         },
         unpairSingle(uuid) {
-          fetch("./api/clients/unpair", { method: "POST", body: JSON.stringify({ uuid }) }).then(() => {
+          fetch("./api/clients/unpair", { 
+            method: "POST", 
+            headers: {
+              'Content-Type': 'application/json'
+            }, 
+            body: JSON.stringify({ uuid }) 
+          }).then(() => {
             this.showApplyMessage = true;
             this.refreshClients();
           });
@@ -263,11 +278,19 @@
           }, 5000);
           fetch("./api/restart", {
             method: "POST",
+            headers: {
+                "Content-Type": "application/json"
+            }
           });
         },
         ddResetPersistence() {
           this.ddResetPressed = true;
-          fetch("/api/reset-display-device-persistence", { method: "POST" })
+          fetch("/api/reset-display-device-persistence", { 
+            method: "POST",
+            headers: { 
+              "Content-Type": "application/json" 
+            } 
+          })
             .then((r) => r.json())
             .then((r) => {
               this.ddResetPressed = false;
diff --git a/src_assets/common/assets/web/welcome.html b/src_assets/common/assets/web/welcome.html
index 2f06c8a1..bdacf941 100644
--- a/src_assets/common/assets/web/welcome.html
+++ b/src_assets/common/assets/web/welcome.html
@@ -78,6 +78,9 @@
         this.loading = true;
         fetch("./api/password", {
           method: "POST",
+          headers: {
+            'Content-Type': 'application/json'
+          },
           body: JSON.stringify(this.passwordData),
         }).then((r) => {
           this.loading = false;