diff --git a/lib/SparkPost/SparkPost.php b/lib/SparkPost/SparkPost.php
index f88d847..3c75803 100644
--- a/lib/SparkPost/SparkPost.php
+++ b/lib/SparkPost/SparkPost.php
@@ -35,7 +35,9 @@ class SparkPost {
    * Sets up instances of sub libraries.
    *
    * @param Ivory\HttpAdapter $httpAdapter - An adapter for making http requests
-   * @param Array $settingsConfig - Hashmap that contains config values for the SDK to connect to SparkPost
+   * @param String | Array $settingsConfig - Hashmap that contains config values
+   *              for the SDK to connect to SparkPost. If its a string we assume that
+   *              its just they API Key.
    */
   public function __construct($httpAdapter, $settingsConfig) {
     //config needs to be setup before adapter because of default adapter settings
@@ -107,10 +109,17 @@ public function setHttpAdapter($httpAdapter) {
 
   /**
    * Allows the user to pass in values to override the defaults and set their API key
-   * @param Array $settingsConfig - Hashmap that contains config values for the SDK to connect to SparkPost
+   * @param String | Array $settingsConfig - Hashmap that contains config values
+   *              for the SDK to connect to SparkPost. If its a string we assume that
+   *              its just they API Key.
    * @throws \Exception
    */
-  public function setConfig(Array $settingsConfig) {
+  public function setConfig($settingsConfig) {
+    // if the config map is a string we should assume that its an api key
+    if (is_string($settingsConfig)) {
+      $settingsConfig = ['key'=>$settingsConfig];
+    }
+
     // Validate API key because its required
     if (!isset($settingsConfig['key']) || empty(trim($settingsConfig['key']))){
       throw new \Exception('You must provide an API key');
diff --git a/test/unit/SparkPostTest.php b/test/unit/SparkPostTest.php
index 101784a..b1b38fe 100644
--- a/test/unit/SparkPostTest.php
+++ b/test/unit/SparkPostTest.php
@@ -51,6 +51,12 @@ public function testSetBadHTTPAdapter() {
     $this->resource->setHttpAdapter(new \stdClass());
   }
 
+  public function testSetConfigStringKey() {
+    $this->resource->setConfig('a key');
+    $config = self::$utils->getProperty($this->resource, 'config');
+    $this->assertEquals('a key', $config['key']);
+  }
+
   /**
    * @expectedException Exception
    * @expectedExceptionMessageRegExp /API key/