diff --git a/src/Bookboon.php b/src/Bookboon.php
index d6bcb62..da716e1 100644
--- a/src/Bookboon.php
+++ b/src/Bookboon.php
@@ -41,30 +41,42 @@ public function __construct(Client $client)
     }
 
     /**
-     * @param $appId
-     * @param $appSecret
+     * @param string $appId
+     * @param string $appSecret
      * @param array $scopes
      * @param array $headers
-     * @param null $appUserId
-     * @param null $redirectUri
+     * @param string|null $appUserId
+     * @param string|null $redirectUri
      * @param Cache|null $cache
      * @return Bookboon
+     * @throws Exception\UsageException
      */
-    public static function create($appId, $appSecret, array $scopes, array $headers = [], $appUserId = null, $redirectUri = null, Cache $cache = null)
-    {
+    public static function create(
+        $appId,
+        $appSecret,
+        array $scopes,
+        array $headers = [],
+        $appUserId = null,
+        $redirectUri = null,
+        Cache $cache = null
+    ) {
         $headersObject = new Headers();
         foreach ($headers as $key => $value) {
             $headersObject->set($key, $value);
         }
 
-        return new Bookboon(new OauthClient($appId, $appSecret, $headersObject, $scopes, $cache, $redirectUri, $appUserId));
+        return new Bookboon(
+            new OauthClient($appId, $appSecret, $headersObject, $scopes, $cache, $redirectUri, $appUserId)
+        );
     }
+
     /**
-     * @param $url
+     * @param string $url
      * @param array $variables
-     * @param $httpMethod
-     * @param bool $shouldCache
+     * @param string $httpMethod
+     * @param boolean $shouldCache
      * @return BookboonResponse
+     * @throws Exception\UsageException
      */
     public function rawRequest($url, array $variables = [], $httpMethod = Client::HTTP_GET, $shouldCache = true)
     {
diff --git a/src/Client/BasicAuthClient.php b/src/Client/BasicAuthClient.php
index 0d38d08..fad0100 100644
--- a/src/Client/BasicAuthClient.php
+++ b/src/Client/BasicAuthClient.php
@@ -15,7 +15,7 @@ class BasicAuthClient implements Client
 {
     use ClientTrait, ResponseTrait, RequestTrait;
 
-    const C_VERSION = '2.0';
+    const C_VERSION = '2.1';
 
     protected static $CURL_REQUESTS;
 
@@ -28,7 +28,18 @@ class BasicAuthClient implements Client
         CURLOPT_SSL_VERIFYHOST => 2,
     );
 
-    public function __construct($apiId, $apiSecret, Headers $headers, Cache $cache = null)
+    protected $_apiUri;
+
+    /**
+     * BasicAuthClient constructor.
+     * @param string $apiId
+     * @param string $apiSecret
+     * @param Headers $headers
+     * @param Cache|null $cache
+     * @param string|null $apiUri
+     * @throws UsageException
+     */
+    public function __construct($apiId, $apiSecret, Headers $headers, Cache $cache = null, $apiUri = null)
     {
         if (empty($apiId) || empty($apiSecret)) {
             throw new UsageException("Key and secret are required");
@@ -38,23 +49,32 @@ public function __construct($apiId, $apiSecret, Headers $headers, Cache $cache =
         $this->setApiSecret($apiSecret);
         $this->setCache($cache);
         $this->setHeaders($headers);
+
+        $this->_apiUri = $this->parseUriOrDefault($apiUri);
     }
 
     /**
      * Makes the actual query call to the remote api.
      *
-     * @param string $url The url relative to the address
+     * @param string $uri The url relative to the address
      * @param string $type Bookboon::HTTP_GET or  Bookboon::HTTP_POST
      * @param array $variables array of post variables (key => value)
-     * @oaram string $contentType
-     *
      * @param string $contentType
      * @return BookboonResponse
+     * @throws ApiAuthenticationException
      * @throws ApiGeneralException
      * @throws ApiTimeoutException
+     * @throws \Bookboon\Api\Exception\ApiNotFoundException
+     * @throws \Bookboon\Api\Exception\ApiSyntaxException
+     * @oaram string $contentType
+     *
      */
-    protected function executeQuery($url, $type = self::HTTP_GET, $variables = array(), $contentType = self::CONTENT_TYPE_FORM)
-    {
+    protected function executeQuery(
+        $uri,
+        $type = self::HTTP_GET,
+        $variables = array(),
+        $contentType = self::CONTENT_TYPE_FORM
+    ) {
         $http = curl_init();
         $headers = $this->getHeaders()->getAll();
 
@@ -70,7 +90,7 @@ protected function executeQuery($url, $type = self::HTTP_GET, $variables = array
         }
 
         curl_setopt($http, CURLOPT_USERAGENT, $this->getUserAgentString());
-        curl_setopt($http, CURLOPT_URL, Client::API_PROTOCOL . "://$url");
+        curl_setopt($http, CURLOPT_URL, $uri);
         curl_setopt($http, CURLOPT_USERPWD, $this->getApiId() . ':' . $this->getApiSecret());
         curl_setopt($http, CURLOPT_HTTPHEADER, $headers);
 
@@ -97,7 +117,7 @@ protected function executeQuery($url, $type = self::HTTP_GET, $variables = array
             substr($response, $headersSize),
             substr($response, 0, $headersSize),
             $httpStatus,
-            $url
+            $uri
         );
 
         return new BookboonResponse($responseArray, $headers);
@@ -153,8 +173,8 @@ public function requestAccessToken(array $options = array(), $type = OauthGrants
     }
 
     /**
-     * @param $variables
-     * @param $contentType
+     * @param array $variables
+     * @param string $contentType
      * @return string
      */
     protected function encodeByContentType(array $variables, $contentType)
@@ -164,7 +184,7 @@ protected function encodeByContentType(array $variables, $contentType)
 
 
     /**
-     * @param $appUserId
+     * @param string $appUserId
      * @throws UsageException
      */
     public function setAct($appUserId)
@@ -202,10 +222,9 @@ public function generateState()
     }
 
     /**
-     * @param $stateParameter
-     * @param $stateSession
-     * @return bool
-     * @throws ApiInvalidStateException
+     * @param string $stateParameter
+     * @param string  $stateSession
+     * @return boolean
      * @throws UsageException
      */
     public function isCorrectState($stateParameter, $stateSession)
@@ -213,8 +232,19 @@ public function isCorrectState($stateParameter, $stateSession)
         throw new UsageException("Not Supported");
     }
 
+    /**
+     * @return string
+     */
     protected function getComponentVersion()
     {
         return self::C_VERSION;
     }
+
+    /**
+     * @return string
+     */
+    protected function getBaseApiUri()
+    {
+        return $this->_apiUri;
+    }
 }
\ No newline at end of file
diff --git a/src/Client/BookboonResponse.php b/src/Client/BookboonResponse.php
index 6d065b5..0864bc8 100644
--- a/src/Client/BookboonResponse.php
+++ b/src/Client/BookboonResponse.php
@@ -9,27 +9,27 @@ class BookboonResponse
     /**
      * @var array
      */
-    protected $returnArray;
+    protected $responseArray;
 
     /**
      * @var array
      */
-    protected $headers;
+    protected $responseHeaders;
 
     /**
-     * @var array
+     * @var EntityStore
      */
     protected $entityStore;
 
     /**
      * BookboonResponse constructor.
-     * @param $returnArray
-     * @param $headers
+     * @param array $responseArray
+     * @param array $responseHeaders
      */
-    public function __construct($returnArray, $headers)
+    public function __construct(array $responseArray, array $responseHeaders)
     {
-        $this->returnArray = $returnArray;
-        $this->headers = $headers;
+        $this->responseArray = $responseArray;
+        $this->responseHeaders = $responseHeaders;
     }
 
     /**
@@ -37,7 +37,8 @@ public function __construct($returnArray, $headers)
      */
     public function getHeaders()
     {
-        return $this->headers;
+
+        return $this->responseHeaders;
     }
 
     /**
@@ -45,11 +46,11 @@ public function getHeaders()
      */
     public function getReturnArray()
     {
-        return $this->returnArray;
+        return $this->responseArray;
     }
 
     /**
-     * @return array
+     * @return EntityStore
      */
     public function getEntityStore()
     {
@@ -57,7 +58,7 @@ public function getEntityStore()
     }
 
     /**
-     * @param $entityStore
+     * @param EntityStore $entityStore
      */
     public function setEntityStore(EntityStore $entityStore)
     {
diff --git a/src/Client/Client.php b/src/Client/Client.php
index b8da812..fdf10ae 100644
--- a/src/Client/Client.php
+++ b/src/Client/Client.php
@@ -19,9 +19,10 @@ interface Client
     const CONTENT_TYPE_FORM = 'application/x-www-form-urlencoded';
 
     const API_PROTOCOL = 'https';
-    const API_URL = 'bookboon.com/api';
+    const API_HOST = 'bookboon.com';
+    const API_PATH = '/api';
 
-    const VERSION = 'Bookboon-PHP/3.0';
+    const VERSION = 'Bookboon-PHP/3.1';
 
     /**
      * Prepares the call to the api and if enabled tries cache provider first for GET calls.
diff --git a/src/Client/Oauth/BookboonProvider.php b/src/Client/Oauth/BookboonProvider.php
index 8de4c78..0b80c6a 100644
--- a/src/Client/Oauth/BookboonProvider.php
+++ b/src/Client/Oauth/BookboonProvider.php
@@ -23,7 +23,7 @@ class BookboonProvider extends AbstractProvider
 
     public function __construct(array $options = [], array $collaborators = [])
     {
-        if (isset($options['baseUri'])) {
+        if (isset($options['baseUri']) && $options['baseUri'] != "") {
             $parts = explode('://', $options['baseUri']);
             $this->protocol = $parts[0];
             $this->host = $parts[1];
diff --git a/src/Client/OauthClient.php b/src/Client/OauthClient.php
index ed51860..5207023 100644
--- a/src/Client/OauthClient.php
+++ b/src/Client/OauthClient.php
@@ -23,7 +23,9 @@ class OauthClient implements Client
 {
     use ClientTrait, ResponseTrait, RequestTrait;
 
-    const C_VERSION = '2.0';
+    const C_VERSION = '2.1';
+
+    protected $_apiUri;
 
     /** @var AccessToken */
     private $accessToken;
@@ -41,12 +43,23 @@ class OauthClient implements Client
      * @param Headers $headers
      * @param array $scopes
      * @param Cache $cache
-     * @param $redirectUri
-     * @param $appUserId
+     * @param string $redirectUri
+     * @param string $appUserId
+     * @param string|null $authServiceUri
+     * @param string|null $apiUri
      * @throws UsageException
      */
-    public function __construct($apiId, $apiSecret, Headers $headers, array $scopes, Cache $cache = null, $redirectUri = null, $appUserId = null)
-    {
+    public function __construct(
+        $apiId,
+        $apiSecret,
+        Headers $headers,
+        array $scopes,
+        Cache $cache = null,
+        $redirectUri = null,
+        $appUserId = null,
+        $authServiceUri = null,
+        $apiUri = null
+    ) {
         if (empty($apiId)) {
             throw new UsageException("Client id is required");
         }
@@ -55,24 +68,31 @@ public function __construct($apiId, $apiSecret, Headers $headers, array $scopes,
             'clientId'      => $apiId,
             'clientSecret'  => $apiSecret,
             'scope'         => $scopes,
-            'redirectUri'   => $redirectUri
+            'redirectUri'   => $redirectUri,
+            'baseUri'       => $authServiceUri
         ]);
 
         $this->setCache($cache);
         $this->setHeaders($headers);
         $this->setAct($appUserId);
+
+        $this->_apiUri = $this->parseUriOrDefault($apiUri);
     }
 
     /**
-     * @param $url
+     * @param string $uri
      * @param string $type
      * @param array $variables
      * @param string $contentType
-     * @return mixed
+     * @return BookboonResponse
      * @throws ApiAccessTokenExpired
      * @throws ApiAuthenticationException
+     * @throws \Bookboon\Api\Exception\ApiGeneralException
+     * @throws \Bookboon\Api\Exception\ApiNotFoundException
+     * @throws \Bookboon\Api\Exception\ApiSyntaxException
+     * @throws \GuzzleHttp\Exception\GuzzleException
      */
-    protected function executeQuery($url, $type = Client::HTTP_GET, $variables = array(), $contentType = Client::CONTENT_TYPE_JSON)
+    protected function executeQuery($uri, $type = Client::HTTP_GET, $variables = array(), $contentType = Client::CONTENT_TYPE_JSON)
     {
         if (!($this->getAccessToken() instanceof AccessToken)) {
             throw new ApiAuthenticationException("Not authenticated");
@@ -83,8 +103,6 @@ protected function executeQuery($url, $type = Client::HTTP_GET, $variables = arr
             'headers' => $this->headers->getHeadersArray()
         ];
         $options['headers']['User-Agent'] = $this->getUserAgentString();
-        
-        $url = Client::API_PROTOCOL . '://' . $url;
 
         if (count($variables) > 0 && $type == Client::HTTP_POST) {
             $postType = $contentType == Client::CONTENT_TYPE_JSON ? 'json' : 'form_params';
@@ -94,7 +112,7 @@ protected function executeQuery($url, $type = Client::HTTP_GET, $variables = arr
         try {
             $request = $this->provider->getAuthenticatedRequest(
                 $type,
-                $url,
+                $uri,
                 $this->getAccessToken()
             );
 
@@ -103,7 +121,6 @@ protected function executeQuery($url, $type = Client::HTTP_GET, $variables = arr
 
             }
         }
-
         catch (IdentityProviderException $e) {
             throw new ApiAuthenticationException("Identity not found");
         }
@@ -121,7 +138,7 @@ protected function executeQuery($url, $type = Client::HTTP_GET, $variables = arr
             $response->getBody()->getContents(),
             $response->getHeaders(),
             $response->getStatusCode(),
-            $url
+            $uri
         );
 
         return new BookboonResponse($responseArray, $response->getHeaders());
@@ -194,7 +211,7 @@ public function generateState()
 
     /**
      * @param AccessToken $accessToken
-     * @return mixed|void
+     * @return void
      * @throws ApiAccessTokenExpired
      */
     public function setAccessToken(AccessToken $accessToken)
@@ -209,9 +226,8 @@ public function setAccessToken(AccessToken $accessToken)
     /**
      * @param $stateParameter
      * @param $stateSession
-     * @return bool
+     * @return boolean
      * @throws ApiInvalidStateException
-     * @throws UsageException
      */
     public function isCorrectState($stateParameter, $stateSession)
     {
@@ -268,13 +284,29 @@ public function getAccessToken()
         return $this->accessToken;
     }
 
+    /**
+     * @param $request
+     * @param $data
+     * @return void
+     */
     protected function reportDeveloperInfo($request, $data)
     {
         // TODO: Implement reportDeveloperInfo() method.
     }
 
+    /**
+     * @return string
+     */
     protected function getComponentVersion()
     {
         return self::C_VERSION;
     }
+
+    /**
+     * @return string
+     */
+    protected function getBaseApiUri()
+    {
+        return $this->_apiUri;
+    }
 }
\ No newline at end of file
diff --git a/src/Client/RequestTrait.php b/src/Client/RequestTrait.php
index 9756b99..9c472a6 100644
--- a/src/Client/RequestTrait.php
+++ b/src/Client/RequestTrait.php
@@ -8,13 +8,18 @@
 trait RequestTrait
 {
     /**
-     * @param $url
+     * @param string $uri
      * @param string $type
      * @param array $variables
      * @param string $contentType
      * @return mixed
      */
-    abstract protected function executeQuery($url, $type = Client::HTTP_GET, $variables = array(), $contentType = 'application/x-www-form-urlencoded');
+    abstract protected function executeQuery(
+        $uri,
+        $type = Client::HTTP_GET,
+        $variables = array(),
+        $contentType = Client::CONTENT_TYPE_FORM
+    );
 
     /**
      * @return Cache|null
@@ -48,7 +53,11 @@ abstract protected function reportDeveloperInfo($request, $data);
      */
     public function makeRequest($relativeUrl, array $variables = array(), $httpMethod = Client::HTTP_GET, $shouldCache = true, $contentType = Client::CONTENT_TYPE_JSON)
     {
-        $queryUrl = Client::API_URL . $relativeUrl;
+        if (strpos($relativeUrl, '/') !== 0) {
+            throw new UsageException('Location must begin with forward slash');
+        }
+
+        $queryUrl = $this->getBaseApiUri() . $relativeUrl;
         $postVariables = array();
 
         if ($httpMethod == Client::HTTP_GET && count($variables) !== 0) {
@@ -59,9 +68,6 @@ public function makeRequest($relativeUrl, array $variables = array(), $httpMetho
             $postVariables = $variables;
         }
 
-        if (substr($relativeUrl, 0, 1) !== '/') {
-            throw new UsageException('Location must begin with forward slash');
-        }
 
         if ($this->getCache() != null && $this->getCache()->isCachable($queryUrl, $httpMethod) && $shouldCache) {
             $result = $this->getFromCache($queryUrl);
@@ -109,4 +115,36 @@ protected function getFromCache($queryUrl)
         return $result;
     }
 
+    /**
+     * @param string $uri
+     * @return string
+     * @throws UsageException
+     */
+    protected function parseUriOrDefault($uri)
+    {
+        $protocol = Client::API_PROTOCOL;
+        $host = Client::API_HOST;
+        $path = Client::API_PATH;
+
+        if (!empty($uri)) {
+            $parts = explode('://', $uri);
+            $protocol = $parts[0];
+            $host = $parts[1];
+            if (strpos($host, '/') !== false) {
+                throw new UsageException('URI must not contain forward slashes');
+            }
+        }
+
+        if ($protocol != 'http' && $protocol != 'https') {
+            throw new UsageException('Invalid protocol specified in URI');
+        }
+
+        return "${protocol}://${host}${path}";
+    }
+
+    /**
+     * @return string
+     */
+    abstract protected function getBaseApiUri();
+
 }
\ No newline at end of file
diff --git a/tests/Client/RequestTraitTest.php b/tests/Client/RequestTraitTest.php
index 2e34c3e..60cd327 100644
--- a/tests/Client/RequestTraitTest.php
+++ b/tests/Client/RequestTraitTest.php
@@ -20,43 +20,47 @@ public function callingBack() {
     public function testPlainGet()
     {
         $mock = $this->getMockForTrait('\Bookboon\Api\Client\RequestTrait');
+        $mock->method("getBaseApiUri")->willReturn(Client::API_HOST . Client::API_PATH);
 
         $mock->method('executeQuery')
              ->will($this->returnCallback(array($this, 'callingBack')));
 
         $mock->makeRequest('/plain_get');
 
-        $this->assertEquals(Client::API_URL . '/plain_get', $this->returnValues[0]);
+        $this->assertEquals(Client::API_HOST . Client::API_PATH . '/plain_get', $this->returnValues[0]);
     }
 
     public function testGetWithQueryString()
     {
         $mock = $this->getMockForTrait('\Bookboon\Api\Client\RequestTrait');
+        $mock->method("getBaseApiUri")->willReturn(Client::API_HOST . Client::API_PATH);
 
         $mock->method('executeQuery')
             ->will($this->returnCallback(array($this, 'callingBack')));
 
         $mock->makeRequest('/get_query_string', array("query2" => "test1"));
 
-        $this->assertEquals(Client::API_URL . '/get_query_string?query2=test1', $this->returnValues[0]);
+        $this->assertEquals(Client::API_HOST . Client::API_PATH . '/get_query_string?query2=test1', $this->returnValues[0]);
     }
 
     public function testPlainPost()
     {
         $mock = $this->getMockForTrait('\Bookboon\Api\Client\RequestTrait');
+        $mock->method("getBaseApiUri")->willReturn(Client::API_HOST . Client::API_PATH);
 
         $mock->method('executeQuery')
             ->will($this->returnCallback(array($this, 'callingBack')));
 
         $mock->makeRequest('/plain_post', array(), Client::HTTP_POST);
 
-        $this->assertEquals(Client::API_URL . '/plain_post', $this->returnValues[0]);
+        $this->assertEquals(Client::API_HOST . Client::API_PATH . '/plain_post', $this->returnValues[0]);
         $this->assertEquals(Client::HTTP_POST, $this->returnValues[1]);
     }
 
     public function testPlainPostWithValues()
     {
         $mock = $this->getMockForTrait('\Bookboon\Api\Client\RequestTrait');
+        $mock->method("getBaseApiUri")->willReturn(Client::API_HOST . Client::API_PATH);
 
         $mock->method('executeQuery')
             ->will($this->returnCallback(array($this, 'callingBack')));
@@ -74,6 +78,7 @@ private function getCacheMock()
     public function testMakeRequestNotCached()
     {
         $mock = $this->getMockForTrait('\Bookboon\Api\Client\RequestTrait');
+        $mock->method("getBaseApiUri")->willReturn(Client::API_HOST . Client::API_PATH);
 
         $cacheMock = $this->getCacheMock();
         $cacheMock->method("get")->willReturn(false);
@@ -89,7 +94,7 @@ public function testMakeRequestNotCached()
         $result = $mock->makeRequest('/plain_get');
 
         $this->assertNull($result);
-        $this->assertEquals(Client::API_URL . '/plain_get', $this->returnValues[0]);
+        $this->assertEquals(Client::API_HOST . Client::API_PATH . '/plain_get', $this->returnValues[0]);
     }
 
     public function testMakeRequestCached()