diff --git a/Civi/API/Kernel.php b/Civi/API/Kernel.php
index 596fdada7266..4b88edddaf7a 100644
--- a/Civi/API/Kernel.php
+++ b/Civi/API/Kernel.php
@@ -86,15 +86,8 @@ public function run($entity, $action, $params, $extra = NULL) {
    * @throws \API_Exception
    */
   public function runSafe($entity, $action, $params, $extra = NULL) {
-    // TODO Define alternative calling convention makes it easier to construct $apiRequest
-    // without the ambiguity of "data" vs "options"
     $apiRequest = Request::create($entity, $action, $params, $extra);
 
-    /**
-     * @var $apiProvider \Civi\API\Provider\ProviderInterface|NULL
-     */
-    $apiProvider = NULL;
-
     try {
       $apiResponse = $this->runRequest($apiRequest);
       return $this->formatResult($apiRequest, $apiResponse);
@@ -159,9 +152,7 @@ public function runAuthorize($entity, $action, $params, $extra = NULL) {
    * @throws \Civi\API\Exception\UnauthorizedException
    */
   public function runRequest($apiRequest) {
-    $this->validate($apiRequest);
-
-    $this->boot();
+    $this->boot($apiRequest);
     $errorScope = \CRM_Core_TemporaryErrorScope::useException();
 
     list($apiProvider, $apiRequest) = $this->resolve($apiRequest);
@@ -169,17 +160,35 @@ public function runRequest($apiRequest) {
     $apiRequest = $this->prepare($apiProvider, $apiRequest);
     $result = $apiProvider->invoke($apiRequest);
 
-    $apiResponse = $this->respond($apiProvider, $apiRequest, $result);
-    return $apiResponse;
+    return $this->respond($apiProvider, $apiRequest, $result);
   }
 
   /**
-   * Bootstrap - Load basic dependencies.
+   * Bootstrap - Load basic dependencies and sanity-check inputs.
+   *
+   * @param \Civi\API\V4\Action|array $apiRequest
+   * @throws \API_Exception
    */
-  public function boot() {
-    require_once 'api/v3/utils.php';
+  public function boot($apiRequest) {
     require_once 'api/Exception.php';
-    _civicrm_api3_initialize();
+
+    if (!is_array($apiRequest['params'])) {
+      throw new \API_Exception('Input variable `params` is not an array', 2000);
+    }
+    switch ($apiRequest['version']) {
+      case 2:
+      case 3:
+        require_once 'api/v3/utils.php';
+        _civicrm_api3_initialize();
+        break;
+
+      case 4:
+        // nothing to do
+        break;
+
+      default:
+        throw new \API_Exception('Unknown api version', 2000);
+    }
   }
 
   /**
@@ -187,11 +196,6 @@ public function boot() {
    * @throws \API_Exception
    */
   protected function validate($apiRequest) {
-    if ($apiRequest['version'] === 3) {
-      if (!is_array($apiRequest['params'])) {
-        throw new \API_Exception('Input variable `params` is not an array', 2000);
-      }
-    }
   }
 
   /**
diff --git a/Civi/API/Request.php b/Civi/API/Request.php
index 361ac5a8a588..f30962d1a735 100644
--- a/Civi/API/Request.php
+++ b/Civi/API/Request.php
@@ -59,83 +59,56 @@ class Request {
    *   - chains: unspecified derived from params [v4-only]
    */
   public static function create($entity, $action, $params, $extra = NULL) {
-    $version = self::parseVersion($params);
-
+    $version = \CRM_Utils_Array::value('version', $params);
     switch ($version) {
-      case 2:
-      case 3:
-        $apiRequest = array(); // new \Civi\API\Request();
+      default:
+        $apiRequest = array();
         $apiRequest['id'] = self::$nextId++;
-        $apiRequest['version'] = $version;
+        $apiRequest['version'] = (int) $version;
         $apiRequest['params'] = $params;
         $apiRequest['extra'] = $extra;
         $apiRequest['fields'] = NULL;
-
-        $apiRequest['entity'] = $entity = self::normalizeEntityName($entity, $apiRequest['version']);
-        $apiRequest['action'] = $action = self::normalizeActionName($action, $apiRequest['version']);
-
+        $apiRequest['entity'] = self::normalizeEntityName($entity, $apiRequest['version']);
+        $apiRequest['action'] = self::normalizeActionName($action, $apiRequest['version']);
         return $apiRequest;
 
       case 4:
         $apiCall = call_user_func(array("Civi\\Api4\\$entity", $action));
+        $apiRequest['id'] = self::$nextId++;
         unset($params['version']);
         foreach ($params as $name => $param) {
           $setter = 'set' . ucfirst($name);
           $apiCall->$setter($param);
         }
         return $apiCall;
-
-      default:
     }
 
   }
 
   /**
-   * Normalize/validate entity and action names
+   * Normalize entity to be CamelCase.
+   *
+   * APIv1-v3 munges entity/action names, and accepts any mixture of case and underscores.
    *
    * @param string $entity
    * @param int $version
    * @return string
-   * @throws \API_Exception
    */
   public static function normalizeEntityName($entity, $version) {
-    if ($version <= 3) {
-      // APIv1-v3 munges entity/action names, and accepts any mixture of case and underscores.
-      // We normalize entity to be CamelCase.
-      return \CRM_Utils_String::convertStringToCamel(\CRM_Utils_String::munge($entity));
-    }
-    else {
-      throw new \API_Exception("Unknown api version");
-    }
-  }
-
-  public static function normalizeActionName($action, $version) {
-    if ($version <= 3) {
-      // APIv1-v3 munges entity/action names, and accepts any mixture of case and underscores.
-      // We normalize action to be lowercase.
-      return strtolower(\CRM_Utils_String::munge($action));
-    }
-    else {
-      throw new \API_Exception("Unknown api version");
-    }
+    return \CRM_Utils_String::convertStringToCamel(\CRM_Utils_String::munge($entity));
   }
 
   /**
-   * We must be sure that every request uses only one version of the API.
+   * Normalize api action name to be lowercase.
    *
-   * @param array $params
-   *   API parameters.
-   * @return int
+   * APIv1-v3 munges entity/action names, and accepts any mixture of case and underscores.
+   *
+   * @param $action
+   * @param $version
+   * @return string
    */
-  protected static function parseVersion($params) {
-    $desired_version = empty($params['version']) ? NULL : (int) $params['version'];
-    if (isset($desired_version) && is_int($desired_version)) {
-      return $desired_version;
-    }
-    else {
-      // we will set the default to version 3 as soon as we find that it works.
-      return 3;
-    }
+  public static function normalizeActionName($action, $version) {
+    return strtolower(\CRM_Utils_String::munge($action));
   }
 
 }
diff --git a/api/api.php b/api/api.php
index 24afbb226219..1e45a143e628 100644
--- a/api/api.php
+++ b/api/api.php
@@ -20,7 +20,7 @@
  * @return array|int
  */
 function civicrm_api($entity, $action, $params, $extra = NULL) {
-  return \Civi::service('civi_api_kernel')->run($entity, $action, $params, $extra);
+  return \Civi::service('civi_api_kernel')->runSafe($entity, $action, $params, $extra);
 }
 
 /**
@@ -40,7 +40,7 @@ function civicrm_api($entity, $action, $params, $extra = NULL) {
  */
 function civicrm_api3($entity, $action, $params = array()) {
   $params['version'] = 3;
-  $result = \Civi::service('civi_api_kernel')->run($entity, $action, $params);
+  $result = \Civi::service('civi_api_kernel')->runSafe($entity, $action, $params);
   if (is_array($result) && !empty($result['is_error'])) {
     throw new CiviCRM_API3_Exception($result['error_message'], CRM_Utils_Array::value('error_code', $result, 'undefined'), $result);
   }