diff --git a/docs/http/test_authorization.http b/docs/http/test_authorization.http
new file mode 100644
index 0000000..8c3b96a
--- /dev/null
+++ b/docs/http/test_authorization.http
@@ -0,0 +1,5 @@
+@term=MA
+
+GET http://localhost:8000/api/dipendenti/cerca?term={{term}}
+Authorization: Basic elixforms_ws:password123
+X-API-Key: myApiAccessToken
diff --git a/public/index.php b/public/index.php
index 78d458c..d4b83a1 100644
--- a/public/index.php
+++ b/public/index.php
@@ -82,7 +82,7 @@ if (strpos($request->path(), '/api/') === 0) {
         $authenticator->authenticate($request);
     } catch (\Throwable $e) {
         $logger->warning('External API auth failed', ['path' => $request->path(), 'error' => $e->getMessage()]);
-        $response->json(['error' => 'Unauthorized'], 401);
+        $response->unauthorized();
     }
 }
 
diff --git a/src/Api/Auth/ApiTokenAuthenticator.php b/src/Api/Auth/ApiTokenAuthenticator.php
index 08d5677..86cbdcc 100644
--- a/src/Api/Auth/ApiTokenAuthenticator.php
+++ b/src/Api/Auth/ApiTokenAuthenticator.php
@@ -15,20 +15,32 @@ class ApiTokenAuthenticator
 
     public function authenticate(Request $request): void
     {
-        $authorization = $_SERVER['HTTP_AUTHORIZATION'] ?? $_SERVER['REDIRECT_HTTP_AUTHORIZATION'] ?? '';
-        if (!$authorization) {
+        $authorizationHeader = $_SERVER['HTTP_AUTHORIZATION'] ?? $_SERVER['REDIRECT_HTTP_AUTHORIZATION'] ?? '';
+        if (!$authorizationHeader) {
             throw new \Exception('Missing Authorization header');
         }
 
-        if (!preg_match('/^Bearer\s+(.*)$/i', trim($authorization), $matches)) {
+        // Basic authorization formal test
+        if (!preg_match('/^Basic\s+(.*)$/i', trim($authorizationHeader), $matches)) {
             throw new \Exception('Invalid Authorization header format');
         }
+        // Username and password test
+        $decoded = explode(':', base64_decode($matches[1]), 2);
+        $authorized = empty(array_diff([ $this->config->secret('api_access_username'), $this->config->secret('api_access_password')], $decoded));
+        if (!$authorized) {
+            throw new \Exception('Authorization failed');
+        }
 
-        $token = $matches[1];
-        $expected = $this->config->secret('api_access_token');
-
-        if (empty($expected) || !hash_equals((string) $expected, (string) $token)) {
-            throw new \Exception('Invalid API access token');
+        // Now, for the X-API-Key only if it was defined in the config (simple way to disable it for testing)
+        $expectedApiKey = $this->config->secret('api_access_token');
+        if ($expectedApiKey !== null && trim($expectedApiKey) !== '') {
+            $apiKeyHeader = $_SERVER['HTTP_X_API_KEY'] ?? $_SERVER['REDIRECT_HTTP_X_API_KEY'] ?? '';
+            if (!$apiKeyHeader) {
+                throw new \Exception('Missing API access token');
+            }
+            if (!hash_equals((string) $expectedApiKey, (string) $apiKeyHeader)) {
+                throw new \Exception('Invalid API access token');
+            }
         }
     }
 }
diff --git a/src/Api/Core/Response.php b/src/Api/Core/Response.php
index 2e5a885..1e2780f 100644
--- a/src/Api/Core/Response.php
+++ b/src/Api/Core/Response.php
@@ -8,4 +8,15 @@ class Response {
         echo json_encode($data);
         exit;
     }
+
+    public function unauthorized(?string $data = null) {
+        http_response_code(401);
+        header('Content-Type: application/json');
+        header('HTTP/1.1 401 Unauthorized');
+        header('Content-Length: 0');
+        if ($data !== null && $data !== '') {
+            echo json_encode($data);
+        }
+        exit;
+    }
 }