diff --git a/cSpell.json b/cSpell.json
index e367ccf59ade..ae826e9af150 100644
--- a/cSpell.json
+++ b/cSpell.json
@@ -435,7 +435,8 @@
         {
             "filename": "**/specification/web/resource-manager/Microsoft.Web/stable/**/WebApps.json",
             "words": [
-                "sitecontainers"
+                "sitecontainers",
+                "updatemachinekey"
             ]
         },
         {
diff --git a/specification/web/resource-manager/Microsoft.Web/stable/2024-04-01/WebApps.json b/specification/web/resource-manager/Microsoft.Web/stable/2024-04-01/WebApps.json
index 6183bee9c28c..1d7342d3af36 100644
--- a/specification/web/resource-manager/Microsoft.Web/stable/2024-04-01/WebApps.json
+++ b/specification/web/resource-manager/Microsoft.Web/stable/2024-04-01/WebApps.json
@@ -6154,6 +6154,52 @@
         }
       }
     },
+    "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Web/sites/{name}/updatemachinekey": {
+      "post": {
+        "tags": [
+          "WebApps"
+        ],
+        "summary": "Updates the machine key of an app.",
+        "operationId": "WebApps_UpdateMachineKey",
+        "parameters": [
+          {
+            "$ref": "#/parameters/resourceGroupNameParameter"
+          },
+          {
+            "name": "name",
+            "in": "path",
+            "description": "Name of the app.",
+            "required": true,
+            "type": "string"
+          },
+          {
+            "$ref": "#/parameters/subscriptionIdParameter"
+          },
+          {
+            "$ref": "#/parameters/apiVersionParameter"
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "schema": {
+              "type": "object"
+            }
+          },
+          "default": {
+            "description": "App Service error response.",
+            "schema": {
+              "$ref": "./CommonDefinitions.json#/definitions/DefaultErrorResponse"
+            }
+          }
+        },
+        "x-ms-examples": {
+          "Updates the machine key for a site": {
+            "$ref": "./examples/UpdateMachineKey.json"
+          }
+        }
+      }
+    },
     "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Web/sites/{name}/migrate": {
       "put": {
         "tags": [
diff --git a/specification/web/resource-manager/Microsoft.Web/stable/2024-04-01/examples/UpdateMachineKey.json b/specification/web/resource-manager/Microsoft.Web/stable/2024-04-01/examples/UpdateMachineKey.json
new file mode 100644
index 000000000000..0074f2e03250
--- /dev/null
+++ b/specification/web/resource-manager/Microsoft.Web/stable/2024-04-01/examples/UpdateMachineKey.json
@@ -0,0 +1,14 @@
+{
+  "parameters": {
+    "subscriptionId": "34adfa4f-cedf-4dc0-ba29-b6d1a69ab345",
+    "resourceGroupName": "rg",
+    "name": "contoso",
+    "api-version": "2024-04-01"
+  },
+  "responses": {
+    "200": {
+      "headers": {},
+      "body": {}
+    }
+  }
+}