diff --git a/modules/bc_api_docs/assets/dist/.DS_Store b/modules/bc_api_docs/assets/dist/.DS_Store
deleted file mode 100644
index cbbf28b..0000000
Binary files a/modules/bc_api_docs/assets/dist/.DS_Store and /dev/null differ
diff --git a/modules/bc_api_docs/assets/dist/js/.DS_Store b/modules/bc_api_docs/assets/dist/js/.DS_Store
deleted file mode 100644
index ac4d3e5..0000000
Binary files a/modules/bc_api_docs/assets/dist/js/.DS_Store and /dev/null differ
diff --git a/modules/bc_api_example/bc_api_example.info.yml b/modules/bc_api_example/bc_api_example.info.yml
index 41064b5..26f3cb9 100644
--- a/modules/bc_api_example/bc_api_example.info.yml
+++ b/modules/bc_api_example/bc_api_example.info.yml
@@ -6,6 +6,7 @@ core_version_requirement: ^10 || ^11
 package: Bluecadet
 
 dependencies:
+  - drupal:taxonomy
   - bc_api_base:bc_api_base
 
 configure: null
diff --git a/modules/bc_api_example/bc_api_example.routing.yml b/modules/bc_api_example/bc_api_example.routing.yml
index bf7b0e5..f9efc64 100644
--- a/modules/bc_api_example/bc_api_example.routing.yml
+++ b/modules/bc_api_example/bc_api_example.routing.yml
@@ -20,3 +20,26 @@ bc_api_example.pirates_detail:
     parameters:
       nid:
         type: entity:node
+
+bc_api_example.cacheable.pirates:
+  path: '/api/cacheable/pirates'
+  methods: [GET, HEAD]
+  defaults:
+    _controller: '\Drupal\bc_api_example\Controller\ApiControllerCacheableResponsePirateExample:getResourceList'
+  requirements:
+    _permission: 'use api'
+  options:
+    _auth: [ 'key_auth' ]
+
+bc_api_example.cacheable.pirates_detail:
+  path: '/api/cacheable/pirates/{nid}'
+  methods: [GET, HEAD]
+  defaults:
+    _controller: '\Drupal\bc_api_example\Controller\ApiControllerCacheableResponsePirateExample:getResource'
+  requirements:
+    _permission: 'use api'
+  options:
+    _auth: [ 'key_auth' ]
+    parameters:
+      nid:
+        type: entity:node
diff --git a/modules/bc_api_example/config/.DS_Store b/modules/bc_api_example/config/.DS_Store
deleted file mode 100644
index 7d6a845..0000000
Binary files a/modules/bc_api_example/config/.DS_Store and /dev/null differ
diff --git a/modules/bc_api_example/src/Controller/ApiControllerCacheableResponsePirateExample.php b/modules/bc_api_example/src/Controller/ApiControllerCacheableResponsePirateExample.php
new file mode 100644
index 0000000..1d8a1ea
--- /dev/null
+++ b/modules/bc_api_example/src/Controller/ApiControllerCacheableResponsePirateExample.php
@@ -0,0 +1,170 @@
+<?php
+
+namespace Drupal\bc_api_example\Controller;
+
+use Drupal\bc_api_base\Controller\ApiControllerBase;
+use Drupal\bc_api_base\CacheableJsonResponseTrait;
+
+/**
+ * Example API Controller Class.
+ *
+ * @ApiDoc(
+ *   params = {
+ *     @ApiParam(
+ *       name = "status",
+ *       type = "bool",
+ *       description = "Filter on node status.",
+ *       default = "TRUE",
+ *     ),
+ *     @ApiParam(
+ *       name = "nat",
+ *       type = "int",
+ *       description = "Filter on nationality. This should use the taxonomy id of the nationality.",
+ *     ),
+ *   }
+ * )
+ */
+class ApiControllerCacheableResponsePirateExample extends ApiControllerBase {
+
+  use CacheableJsonResponseTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getApiCacheTime($id = NULL) {
+    // Parent method looks at settings form and takes into account list or
+    // detail.
+    return 0;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheId() {
+    // This should be a unique string, characters only.
+    $cid = "yo-ho-ho";
+
+    if (!empty($this->params)) {
+      $cid .= ":" . implode(":", $this->params);
+    }
+
+    $cid .= ":page-" . $this->page;
+    $cid .= ":limit-" . $this->limit;
+
+    return $cid;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function initCacheTags() {
+    $this->cacheTags = [
+      'myAwesomeCoolCacheTag',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setParams() {
+    // It would be good to always run this.
+    parent::setParams();
+
+    $this->privateParams['status'] = 1;
+
+    // Here we also want to handle any bad param errors...
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefaultPlatform() {
+    return "cinder";
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getResourceQueryResult() {
+    // Just having this here as an example.
+    // Most times no need to override this method.
+    parent::getResourceQueryResult();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getResourceListQueryResult() {
+    // This method should be overridden for any endpoint.
+    $query = $this->entityTypeManager->getStorage('node')->getQuery();
+    $query->accessCheck(TRUE);
+    $query->condition('status', $this->privateParams['status']);
+    $query->condition('type', 'pirate');
+
+    $count_query = clone $query;
+
+    $query->range(($this->page * $this->limit), $this->limit);
+    $entity_ids = $query->execute();
+
+    // Must set total result count so we can properly page.
+    $this->resultTotal = (int) $count_query->count()->execute();
+
+    // Process Items.
+    $nodes = $this->entityTypeManager->getStorage('node')->loadMultiple($entity_ids);
+
+    $this->rawData = $nodes;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildAllResourceData() {
+    $data = [];
+
+    foreach ($this->rawData as $node) {
+      $this->cacheTags = array_merge($this->cacheTags, $node->getCacheTags());
+      $this->addCacheableDependency($node);
+      $created_changed = $this->transformer->createdChangedFieldVals($node);
+
+      $item = [
+        'nid' => (int) $node->id(),
+        'cms_title' => $node->label(),
+        'created' => $created_changed[0],
+        'updated' => $created_changed[1],
+      ];
+      $data[] = $item;
+    }
+
+    $this->data = $data;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildLinks() {
+    // This method should be overridden for any endpoint.
+    $base_url = $this->request->getSchemeAndHttpHost() . $this->request->getPathInfo();
+    $tmp_query_params = $this->params;
+    $tmp_query_params['platform'] = $this->platform;
+    $tmp_query_params['limit'] = $this->limit;
+
+    if ($this->page == 0) {
+      $this->prev = "";
+    }
+    else {
+      $tmp_query_params['page'] = $this->page - 1;
+      $this->prev = $base_url . "?" . http_build_query($tmp_query_params);
+    }
+
+    if ($this->resultTotal > (($this->page + 1) * $this->limit)) {
+      $tmp_query_params['page'] = $this->page + 1;
+      $this->next = $base_url . "?" . http_build_query($tmp_query_params);
+    }
+    else {
+
+      $this->next = "";
+    }
+
+  }
+
+}
diff --git a/modules/bc_api_example/src/Controller/ApiControllerPirateExample.php b/modules/bc_api_example/src/Controller/ApiControllerPirateExample.php
index 81ced00..aaedb20 100644
--- a/modules/bc_api_example/src/Controller/ApiControllerPirateExample.php
+++ b/modules/bc_api_example/src/Controller/ApiControllerPirateExample.php
@@ -38,7 +38,8 @@ public function getApiCacheTime($id = NULL) {
    * {@inheritdoc}
    */
   public function getCacheId() {
-    $cid = "SOMETHING_UNIQUE";
+    // This should be a unique string, characters only.
+    $cid = "pirates";
 
     if (!empty($this->params)) {
       $cid .= ":" . implode(":", $this->params);
@@ -93,6 +94,7 @@ public function getResourceQueryResult() {
   public function getResourceListQueryResult() {
     // This method should be overridden for any endpoint.
     $query = $this->entityTypeManager->getStorage('node')->getQuery();
+    $query->accessCheck(TRUE);
     $query->condition('status', $this->privateParams['status']);
     $query->condition('type', 'pirate');
 
diff --git a/modules/bc_api_logger/config/.DS_Store b/modules/bc_api_logger/config/.DS_Store
deleted file mode 100644
index 85dc110..0000000
Binary files a/modules/bc_api_logger/config/.DS_Store and /dev/null differ
diff --git a/src/CacheableJsonResponseTrait.php b/src/CacheableJsonResponseTrait.php
new file mode 100644
index 0000000..f4d8f42
--- /dev/null
+++ b/src/CacheableJsonResponseTrait.php
@@ -0,0 +1,92 @@
+<?php
+
+namespace Drupal\bc_api_base;
+
+use Drupal\Core\Cache\CacheableJsonResponse;
+use Drupal\Core\Cache\CacheableMetadata;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Trait CacheableJsonResponseTrait.
+ *
+ * This trait provides a way to create cacheable JSON responses. It allows for
+ * the addition of cacheable metadata and dependencies to the response, ensuring
+ * that the response can be cached appropriately.
+ */
+trait CacheableJsonResponseTrait {
+
+  /**
+   * Cacheable metadata for the response.
+   *
+   * @var \Drupal\Core\Cache\CacheableMetadata
+   */
+  protected $cacheMetadata = NULL;
+
+  /**
+   * Returns the cacheable metadata for the response.
+   *
+   * When building any data, cacheable metadata should be set from there. And it
+   * will be applied when the request is altered.
+   *
+   * @return \Drupal\Core\Cache\CacheableMetadata
+   */
+  protected function getCacheableMetadata(): CacheableMetadata {
+    if (!isset($this->cacheMetadata)) {
+      $this->cacheMetadata = new CacheableMetadata();
+    }
+    return $this->cacheMetadata;
+  }
+
+  /**
+   * Adds a dependency on an object: merges its cacheability metadata.
+   *
+   * For instance, when a response depends on some configuration, an entity, or
+   * an access result, we must make sure their cacheability metadata is present
+   * on the response. This method makes doing that simple.
+   *
+   * @param \Drupal\Core\Cache\CacheableDependencyInterface|mixed $dependency
+   *   The dependency. If the object implements CacheableDependencyInterface,
+   *   then its cacheability metadata will be used. Otherwise, the passed in
+   *   object must be assumed to be uncacheable, so max-age 0 is set.
+   *
+   * @return $this
+   */
+  public function addCacheableDependency($dependency) {
+
+    $this->cacheMetadata = $this->getCacheableMetadata()->merge(CacheableMetadata::createFromObject($dependency));
+
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getResourceQueryResult() {
+    parent::getResourceQueryResult();
+
+    // If the resource is set, add it as a cacheable dependency.
+    if (isset($this->resource) && !empty($this->resource)) {
+      $this->addCacheableDependency($this->resource);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   *
+   * Override the base classes response, to create a cacheable response.
+   */
+  public function createResponse(): Response {
+    $response = new CacheableJsonResponse($this->return_data);
+
+    // Attach cache metadata if available.
+    if ($cache_metadata = $this->getCacheableMetadata()) {
+      $response->addCacheableDependency($cache_metadata);
+    }
+
+    // Alter it.
+    $this->responseAlter($response);
+
+    return $response;
+  }
+
+}
diff --git a/src/Controller/ApiControllerBase.php b/src/Controller/ApiControllerBase.php
index e86e370..41f44ff 100644
--- a/src/Controller/ApiControllerBase.php
+++ b/src/Controller/ApiControllerBase.php
@@ -464,9 +464,8 @@ final public function getResource(Request $request) {
       return [];
     }
 
-    $response = new JsonResponse($this->return_data);
-    // Alter it.
-    $this->responseAlter($response);
+    // $response = new JsonResponse($this->return_data);
+    $response = $this->createResponse();
 
     return $response;
   }
@@ -533,9 +532,7 @@ final public function getResourceList(Request $request) {
       return [];
     }
 
-    $response = new JsonResponse($this->return_data);
-    // Alter it.
-    $this->responseAlter($response);
+    $response = $this->createResponse();
 
     return $response;
   }
@@ -589,6 +586,19 @@ public function buildLinks() {
     $this->next = "";
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function createResponse(): Response {
+    $response = new JsonResponse($this->return_data);
+    $response->setStatusCode($this->return_data['status']);
+
+    // Allow subclasses to alter it.
+    $this->responseAlter($response);
+
+    return $response;
+  }
+
   /**
    * {@inheritdoc}
    */
diff --git a/src/Controller/ApiControllerInterface.php b/src/Controller/ApiControllerInterface.php
index 211cc9c..476cf5f 100644
--- a/src/Controller/ApiControllerInterface.php
+++ b/src/Controller/ApiControllerInterface.php
@@ -74,8 +74,23 @@ public function getResource(Request $request);
    */
   public function getResourceList(Request $request);
 
+  /**
+   * Create the response object.
+   *
+   * We allow subclasses to override this method if they need to create
+   * different types of responses, however, they can also alter the response
+   * later, if they only need minor changes.
+   *
+   * @return Symfony\Component\HttpFoundation\Response
+   *   The response object.
+   */
+  public function createResponse(): Response;
+
   /**
    * Alter the response object before executing.
+   *
+   * @param \Symfony\Component\HttpFoundation\Response $response
+   *   The response object to alter.
    */
   public function responseAlter(Response $response);
 
diff --git a/src/EventSubscriber/ApiSubscriber.php b/src/EventSubscriber/ApiSubscriber.php
index 361b558..e377b1a 100644
--- a/src/EventSubscriber/ApiSubscriber.php
+++ b/src/EventSubscriber/ApiSubscriber.php
@@ -138,9 +138,10 @@ public function onException($event) {
   public function on400(RequestEvent $event) {
 
     $request = $event->getRequest();
+    $path = $request->getPathInfo();
     $exception = $event->getThrowable();
 
-    if (strpos($request->getRequestUri(), "/api/") === 0 || $request->getRequestUri() == "/api") {
+    if (strpos($request->getRequestUri(), "/api/") === 0 || $path == "/api") {
       $data = [
         'status' => (int) $exception->getStatusCode(),
         'error_msg' => 'Bad Request',
@@ -163,9 +164,10 @@ public function on400(RequestEvent $event) {
   public function on403(RequestEvent $event) {
 
     $request = $event->getRequest();
+    $path = $request->getPathInfo();
     $exception = $event->getThrowable();
 
-    if (strpos($request->getRequestUri(), "/api/") === 0 || $request->getRequestUri() == "/api") {
+    if (strpos($request->getRequestUri(), "/api/") === 0 || $path == "/api") {
 
       $data = [
         'status' => (int) $exception->getStatusCode(),
@@ -189,9 +191,10 @@ public function on403(RequestEvent $event) {
   public function on404(RequestEvent $event) {
 
     $request = $event->getRequest();
+    $path = $request->getPathInfo();
     $exception = $event->getThrowable();
 
-    if (strpos($request->getRequestUri(), "/api/") === 0 || $request->getRequestUri() == "/api") {
+    if (strpos($request->getRequestUri(), "/api/") === 0 || $path == "/api") {
       $data = [
         'status' => (int) $exception->getStatusCode(),
         'error_msg' => 'Not Found',
@@ -201,7 +204,7 @@ public function on404(RequestEvent $event) {
       $event->setResponse($response);
 
       // Log this call.
-      $this->loggerFactory->get('bc_api')->error("403: Bad Api call. " . $exception->getMessage(), ["request" => $request, "exception" => $exception]);
+      $this->loggerFactory->get('bc_api')->error("404: Bad Api call. " . $exception->getMessage(), ["request" => $request, "exception" => $exception]);
     }
 
   }
diff --git a/tests/src/.DS_Store b/tests/src/.DS_Store
deleted file mode 100644
index ba4994a..0000000
Binary files a/tests/src/.DS_Store and /dev/null differ
diff --git a/tests/src/Functional/ResponseTests.php b/tests/src/Functional/ResponseTests.php
index 404f5b2..04a70d6 100644
--- a/tests/src/Functional/ResponseTests.php
+++ b/tests/src/Functional/ResponseTests.php
@@ -30,7 +30,7 @@ class ResponseTests extends BrowserTestBase {
    */
   protected $keyAuthConfig;
 
-  protected $defaultTheme = 'classy';
+  protected $defaultTheme = 'stable9';
 
   protected $dumpHeaders = TRUE;
 
@@ -55,7 +55,7 @@ class ResponseTests extends BrowserTestBase {
   /**
    * {@inheritdoc}
    */
-  protected function setUp() {
+  protected function setUp(): void {
     parent::setUp();
 
     $this->keyAuth = $this->container->get('key_auth');
@@ -88,7 +88,7 @@ public function testHttpResponses() {
     $user = $this->drupalCreateUser(['use api', 'use key authentication']);
 
     // Log in.
-    $this->drupalLogin($user);
+    // $this->drupalLogin($user);
 
     // Call with Query param.
     $this->drupalGet('api/pirates', [
@@ -112,7 +112,7 @@ public function testResponseData() {
     $user = $this->drupalCreateUser(['use key authentication', 'use api']);
 
     // Log in.
-    $this->drupalLogin($user);
+    // $this->drupalLogin($user);
 
     // Call with Query param.
     $data = $this->drupalGet('api/pirates', [
@@ -128,7 +128,7 @@ public function testResponseData() {
     $this->drupalGet('api/pirates', [], ['api-key' => $user->api_key->value]);
     $this->assertSession()->statusCodeEquals(200);
 
-    Drupal::moduleHandler()->loadInclude('bc_api_example', 'inc', 'bc_api_example.data');
+    \Drupal::moduleHandler()->loadInclude('bc_api_example', 'inc', 'bc_api_example.data');
 
     // Check we have a proper result count.
     $pirates = bc_api_example_get_pirates_data();
@@ -139,4 +139,42 @@ public function testResponseData() {
 
   }
 
+  /**
+   * Test the cacheable pirates API endpoint.
+   */
+  public function testCacheablePiratesApiResponse() {
+    // Create API user.
+    $user = $this->drupalCreateUser(['use api', 'use key authentication']);
+    $this->drupalLogin($user);
+
+    // Call the endpoint with the API key as a query param.
+    $this->drupalGet('api/cacheable/pirates', [
+      'query' => [
+        'api-key' => $user->api_key->value,
+      ],
+    ]);
+    $this->assertSession()->statusCodeEquals(200);
+
+    // Check for JSON content type header.
+    $headers = $this->getSession()->getResponseHeaders();
+
+    $this->assertArrayHasKey('Content-Type', $headers);
+    $this->assertStringContainsString('application/json', $headers['Content-Type'][0]);
+
+    // Check for cache headers.
+    $this->assertArrayHasKey('X-Drupal-Cache-Tags', $headers, 'Cache tags header is present');
+    $this->assertArrayHasKey('Cache-Control', $headers, 'Cache-Control header is present');
+
+    // Check the response body.
+    $data = json_decode($this->getSession()->getPage()->getContent(), TRUE);
+    $this->assertIsArray($data['data']);
+    $this->assertArrayHasKey('resultTotal', $data);
+    $this->assertArrayHasKey('data', $data);
+
+    // Check that at least one pirate has a cms_title.
+    if (!empty($data['data'])) {
+      $this->assertArrayHasKey('cms_title', $data['data'][0]);
+    }
+  }
+
 }
diff --git a/tests/src/Unit/CacheableJsonResponseTraitTest.php b/tests/src/Unit/CacheableJsonResponseTraitTest.php
new file mode 100644
index 0000000..f304096
--- /dev/null
+++ b/tests/src/Unit/CacheableJsonResponseTraitTest.php
@@ -0,0 +1,87 @@
+<?php
+
+namespace Drupal\Tests\bc_api_base\Unit;
+
+use Drupal\bc_api_base\CacheableJsonResponseTrait;
+use Drupal\bc_api_base\Controller\ApiControllerBase;
+use Drupal\Core\Cache\CacheableJsonResponse;
+use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Tests\UnitTestCase;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Unit Tests for CacheableJsonResponseTrait.
+ *
+ * @coversDefaultClass \Drupal\bc_api_base\CacheableJsonResponseTrait
+ * @group bc_api_base
+ */
+class CacheableJsonResponseTraitTest extends UnitTestCase {
+
+  /**
+   * Provides a test double for the trait.
+   */
+  protected function getTestController(array $return_data = ['foo' => 'bar']) {
+    return new class($return_data) extends ApiControllerBase {
+      use CacheableJsonResponseTrait;
+
+      public function __construct($return_data) {
+        $this->return_data = $return_data;
+      }
+
+      public function setCacheTags(array $tags) {
+        $this->getCacheableMetadata()->setCacheTags($tags);
+      }
+
+      /**
+       * Public wrapper for testing the protected method.
+       */
+      public function getCacheableMetadataPublic() {
+        return $this->getCacheableMetadata();
+      }
+
+      /**
+       * Public wrapper for the protected cacheableJsonResponse method.
+       */
+      public function cacheableJsonResponsePublic(Response $response) {
+        return $this->cacheableJsonResponse($response);
+      }
+
+    };
+  }
+
+  /**
+   * Tests that getCacheableMetadata returns an instance of CacheableMetadata.
+   */
+  public function testGetCacheableMetadataReturnsObject() {
+    $controller = $this->getTestController();
+    $metadata = $controller->getCacheableMetadataPublic();
+    $this->assertInstanceOf(CacheableMetadata::class, $metadata);
+  }
+
+  /**
+   * Tests that addCacheableDependency merges cacheable metadata.
+   */
+  public function testSetAndGetCacheTags() {
+    $controller = $this->getTestController();
+    $tags = ['foo:1', 'bar:2'];
+    $controller->setCacheTags($tags);
+    $metadata = $controller->getCacheableMetadataPublic();
+    $this->assertEquals($tags, $metadata->getCacheTags());
+  }
+
+  /**
+   * Tests that cacheableJsonResponse returns a CacheableJsonResponse.
+   */
+  public function testCreateResponseReturnsCacheableJsonResponse() {
+    $controller = $this->getTestController(['baz' => 'qux']);
+    $controller->setCacheTags(['baz:1']);
+    $response = $controller->createResponse();
+    $this->assertInstanceOf(CacheableJsonResponse::class, $response);
+    $this->assertEquals(json_encode(['baz' => 'qux']), $response->getContent());
+    $this->assertEquals(200, $response->getStatusCode());
+    // Check cache tags are present.
+    $metadata = $response->getCacheableMetadata();
+    $this->assertContains('baz:1', $metadata->getCacheTags());
+  }
+
+}
diff --git a/tests/src/Unit/QueryValidationTests.php b/tests/src/Unit/QueryValidationTests.php
index 4cd35cf..a85e058 100644
--- a/tests/src/Unit/QueryValidationTests.php
+++ b/tests/src/Unit/QueryValidationTests.php
@@ -20,7 +20,7 @@ class QueryValidationTests extends UnitTestCase {
   /**
    * {@inheritdoc}
    */
-  public function setUp() {
+  protected function setUp(): void {
     // Nothing to do here.
     parent::setUp();
   }