diff --git a/.gitignore b/.gitignore
index f13d388b..59f07e53 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@ composer.phar
 vendor/
 .env
 index.php
-storage.txt
\ No newline at end of file
+storage.txt
+composer.lock
\ No newline at end of file
diff --git a/composer.json b/composer.json
index a72c56ee..2a48c31b 100644
--- a/composer.json
+++ b/composer.json
@@ -15,15 +15,9 @@
             "email": "info@picqer.com"
         }
     ],
-    "repositories": [
-        {
-            "type": "vcs",
-            "url": "https://github.com/picqer/guzzle-oauth2-plugin"
-        }
-    ],
     "require": {
-        "php": ">=5.4.0",
-        "commerceguys/guzzle-oauth2-plugin": "~1.0"
+        "php": ">=5.5.0",
+        "guzzlehttp/guzzle": "~6.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/example.php b/example.php
new file mode 100644
index 00000000..7de1eafb
--- /dev/null
+++ b/example.php
@@ -0,0 +1,88 @@
+<?php
+
+require 'vendor/autoload.php';
+
+function getValue($key)
+{
+    $storage = json_decode(file_get_contents('storage.json'), true);
+    if (array_key_exists($key, $storage)) {
+        return $storage[$key];
+    }
+    return null;
+}
+
+function setValue($key, $value)
+{
+    $storage       = json_decode(file_get_contents('storage.json'), true);
+    $storage[$key] = $value;
+    file_put_contents('storage.json', json_encode($storage));
+}
+
+function authorize()
+{
+    $connection = new \Picqer\Financials\Exact\Connection();
+    $connection->setRedirectUrl('YOUR_REDIRECT_URL');
+    $connection->setExactClientId('YOUR_CLIENT_ID');
+    $connection->setExactClientSecret('YOUR_CLIENT_SECRET');
+    $connection->redirectForAuthorization();
+}
+
+function connect()
+{
+    $connection = new \Picqer\Financials\Exact\Connection();
+    $connection->setRedirectUrl('YOUR_REDIRECT_URL');
+    $connection->setExactClientId('YOUR_CLIENT_ID');
+    $connection->setExactClientSecret('YOUR_CLIENT_SECRET');
+
+    if (getValue('authorizationcode')) // Retrieves authorizationcode from database
+    {
+        $connection->setAuthorizationCode(getValue('authorizationcode'));
+    }
+
+    if (getValue('accesstoken')) // Retrieves accesstoken from database
+    {
+        $connection->setAccessToken(getValue('accesstoken'));
+    }
+
+    if (getValue('refreshtoken')) // Retrieves refreshtoken from database
+    {
+        $connection->setRefreshToken(getValue('refreshtoken'));
+    }
+
+    if (getValue('expires_in')) // Retrieves expires from database
+    {
+        $connection->setTokenExpires(getValue('expires_in'));
+    }
+
+    // Make the client connect and exchange tokens
+    try {
+        $connection->connect();
+    } catch (\Exception $e) {
+        throw new Exception('Could not connect to Exact: ' . $e->getMessage());
+    }
+
+    // Save the new tokens for next connections
+    setValue('accesstoken', $connection->getAccessToken());
+    setValue('refreshtoken', $connection->getRefreshToken());
+    setValue('expires_in', $connection->getTokenExpires());
+
+    return $connection;
+}
+
+if (isset($_GET['code']) && is_null(getValue('authorizationcode'))) {
+    setValue('authorizationcode', $_GET['code']);
+}
+
+$connection = connect();
+
+try {
+    $journals = new \Picqer\Financials\Exact\Journal($connection);
+    $result   = $journals->get();
+    foreach ($result as $journal) {
+        echo 'journal: ' . $journal->Description . '<br>';
+    }
+
+    echo 'done';
+} catch (\Exception $e) {
+    echo get_class($e) . ' : ' . $e->getMessage();
+}
diff --git a/example/example.php b/example/example.php
index 448c3109..ed05b2b3 100644
--- a/example/example.php
+++ b/example/example.php
@@ -72,7 +72,7 @@ function connect()
 
     // Make the client connect and exchange tokens
     try {
-        $connection->client();
+        $connection->connect();
     } catch (\Exception $e) {
         throw new Exception('Could not connect to Exact: ' . $e->getMessage());
     }
diff --git a/src/Picqer/Financials/Exact/Connection.php b/src/Picqer/Financials/Exact/Connection.php
index 4269a8c3..34193271 100644
--- a/src/Picqer/Financials/Exact/Connection.php
+++ b/src/Picqer/Financials/Exact/Connection.php
@@ -1,28 +1,62 @@
 <?php namespace Picqer\Financials\Exact;
 
-use CommerceGuys\Guzzle\Plugin\Oauth2\GrantType\AuthorizationCode;
-use CommerceGuys\Guzzle\Plugin\Oauth2\GrantType\RefreshToken;
-use CommerceGuys\Guzzle\Plugin\Oauth2\Oauth2Plugin;
-use Guzzle\Http\Client;
-use Guzzle\Http\Exception\ClientErrorResponseException;
-use Guzzle\Http\Exception\ServerErrorResponseException;
-use Guzzle\Http\Message\Response;
-use Guzzle\Log\ArrayLogAdapter;
-use Guzzle\Log\MessageFormatter;
-use Guzzle\Plugin\Log\LogPlugin;
-
-class Connection {
+use GuzzleHttp\Client;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
 
+/**
+ * Class Connection
+ * @package Picqer\Financials\Exact
+ */
+class Connection
+{
+
+    /**
+     * @var string
+     */
     private $apiUrl = 'https://start.exactonline.nl/api/v1';
+    /**
+     * @var string
+     */
     private $authUrl = 'https://start.exactonline.nl/api/oauth2/auth';
+    /**
+     * @var string
+     */
     private $tokenUrl = 'https://start.exactonline.nl/api/oauth2/token';
 
+    /**
+     * @var
+     */
     private $exactClientId;
+    /**
+     * @var
+     */
     private $exactClientSecret;
+    /**
+     * @var
+     */
     private $authorizationCode;
+    /**
+     * @var
+     */
     private $accessToken;
+
+    /**
+     * @var
+     */
+    private $tokenExpires;
+
+    /**
+     * @var
+     */
     private $refreshToken;
+    /**
+     * @var
+     */
     private $redirectUrl;
+    /**
+     * @var
+     */
     private $division;
 
     /**
@@ -30,72 +64,152 @@ class Connection {
      */
     private $client;
 
-    public function client()
+    /**
+     * @return Client
+     */
+    private function client()
     {
-        if ($this->client) return $this->client;
-
-        $this->client = new Client($this->apiUrl);
-        $this->client->setDefaultOption('headers/Accept', 'application/json');
-        $this->client->setDefaultOption('headers/Content-Type', 'application/json');
+        if ($this->client) {
+            return $this->client;
+        }
 
-        $this->authenticate();
+        $this->client = new Client([
+            'http_errors' => true,
+        ]);
 
         return $this->client;
     }
 
-    public function get($url, array $params = [])
+    public function connect()
     {
-        if ($url !== 'current/Me') $this->addDivisionNumberToApiUrl();
+        // Redirect for authorization if needed (no access token or refresh token given)
+        if ($this->needsAuthentication()) {
+            $this->redirectForAuthorization();
+        }
+
+        // If access token is not set or token has expired, acquire new token
+        if (empty($this->accessToken) || $this->tokenHasExpired()) {
+            $this->acquireAccessToken();
+        }
 
-        $request = $this->client()->createRequest('GET', $url);
+        $client = $this->client();
 
-        $query = $request->getQuery();
+        return $client;
+    }
 
-        foreach ($params as $paramName => $paramValue)
-        {
-            $query->set($paramName, $paramValue);
+    /**
+     * @param string $method
+     * @param $endpoint
+     * @param null $body
+     * @param array $params
+     * @param array $headers
+     * @return Request
+     */
+    private function createRequest($method = 'GET', $endpoint, $body = null, array $params = [], array $headers = [])
+    {
+        // Add default json headers to the request
+        $headers = array_merge($headers, [
+            'Accept' => 'application/json',
+            'Content-Type' => 'application/json'
+        ]);
+
+        // If access token is not set or token has expired, acquire new token
+        if (empty($this->accessToken) || $this->tokenHasExpired()) {
+            $this->acquireAccessToken();
         }
 
-        $result = $this->client()->send($request);
+        // If we have a token, sign the request
+        if (!$this->needsAuthentication() && !empty($this->accessToken)) {
+            $headers['Authorization'] = 'Bearer ' . $this->accessToken;
+        }
+
+        // Create param string
+        if (!empty($params)) {
+            $endpoint .= '?' . http_build_query($params);
+        }
+
+        // Create the request
+        $request = new Request($method, $endpoint, $headers, $body);
 
-        return $this->parseResult($result);
+        return $request;
     }
 
+    /**
+     * @param $url
+     * @param array $params
+     * @return mixed
+     * @throws ApiException
+     */
+    public function get($url, array $params = [])
+    {
+        $url = $this->formatUrl($url, $url !== 'current/Me');
+
+        $request = $this->createRequest('GET', $url, null, $params);
+
+        $response = $this->client()->send($request);
+
+        return $this->parseResponse($response);
+    }
+
+    /**
+     * @param $url
+     * @param $body
+     * @return mixed
+     * @throws ApiException
+     */
     public function post($url, $body)
     {
-        $this->addDivisionNumberToApiUrl();
-        try
-        {
-            $result = $this->client()->post($url, null, $body)->send();
-        } catch (ServerErrorResponseException $e)
-        {
-            throw new ApiException($e->getResponse()->getBody(true));
+        $url = $this->formatUrl($url);
+
+        try {
+            $request  = $this->createRequest('POST', $url, $body);
+            $response = $this->client()->send($request);
+        } catch (\Exception $e) {
+            throw new ApiException($e->getMessage());
         }
 
-        return $this->parseResult($result);
+        return $this->parseResponse($response);
     }
 
+    /**
+     * @param $url
+     * @param $body
+     * @return mixed
+     * @throws ApiException
+     */
     public function put($url, $body)
     {
-        $this->addDivisionNumberToApiUrl();
-        $result = $this->client()->put($url, null, $body)->send();
+        $url = $this->formatUrl($url);
+
+        $request  = $this->createRequest('PUT', $url, $body);
+        $response = $this->client()->send($request);
 
-        return $this->parseResult($result);
+        return $this->parseResponse($response);
     }
 
+    /**
+     * @param $url
+     * @return mixed
+     * @throws ApiException
+     */
     public function delete($url)
     {
-        $this->addDivisionNumberToApiUrl();
-        $result = $this->client()->delete($url)->send();
+        $url = $this->formatUrl($url);
+
+        $request  = $this->createRequest('DELETE', $url);
+        $response = $this->client()->send($request);
 
-        return $this->parseResult($result);
+        return $this->parseResponse($response);
     }
 
-    public function getAuthUrl()
+    /**
+     * @return string
+     */
+    private function getAuthUrl()
     {
         return $this->authUrl . '?' . http_build_query(array(
-            'client_id'     => $this->exactClientId,
-            'redirect_uri'  => $this->redirectUrl,
+            'client_id' => $this->exactClientId,
+            'redirect_uri' => $this->redirectUrl,
             'response_type' => 'code'
         ));
     }
@@ -140,36 +254,14 @@ public function setRefreshToken($refreshToken)
         $this->refreshToken = $refreshToken;
     }
 
-    public function authenticate()
-    {
-        $params = array(
-            'code'          => $this->authorizationCode,
-            'redirect_uri'  => $this->redirectUrl,
-            'client_id'     => $this->exactClientId,
-            'client_secret' => $this->exactClientSecret,
-            'refresh_token' => $this->refreshToken
-        );
-
-        $oauth2Client = new Client($this->tokenUrl);
-        $grantType = new AuthorizationCode($oauth2Client, $params);
-        $refreshTokenGrantType = new RefreshToken($oauth2Client, $params);
-        $oauth2Plugin = new Oauth2Plugin($grantType, $refreshTokenGrantType);
-        if (! empty($this->refreshToken))
-            $oauth2Plugin->setRefreshToken($this->refreshToken);
-
-        $this->accessToken = $oauth2Plugin->getAccessToken();
-        $this->refreshToken = $oauth2Plugin->getRefreshToken();
-
-        $this->client()->addSubscriber($oauth2Plugin);
-    }
 
+    /**
+     *
+     */
     public function redirectForAuthorization()
     {
-        header('Location: ' . $this->getAuthUrl(
-                $this->exactClientId,
-                $this->redirectUrl
-            )
-        );
+        $authUrl = $this->getAuthUrl();
+        header('Location: ' . $authUrl);
         exit;
     }
 
@@ -181,22 +273,26 @@ public function setRedirectUrl($redirectUrl)
         $this->redirectUrl = $redirectUrl;
     }
 
+    /**
+     * @return bool
+     */
     public function needsAuthentication()
     {
         return empty($this->refreshToken) && empty($this->authorizationCode);
     }
 
-    public function parseResult(Response $response)
+    /**
+     * @param Response $response
+     * @return mixed
+     * @throws ApiException
+     */
+    private function parseResponse(Response $response)
     {
-        try
-        {
-            $json = $response->json();
-            if (array_key_exists('d', $json))
-            {
-                if (array_key_exists('results', $json['d']))
-                {
-                    if (count($json['d']['results']) == 1)
-                    {
+        try {
+            $json = json_decode($response->getBody()->getContents(), true);
+            if (array_key_exists('d', $json)) {
+                if (array_key_exists('results', $json['d'])) {
+                    if (count($json['d']['results']) == 1) {
                         return $json['d']['results'][0];
                     }
 
@@ -207,21 +303,22 @@ public function parseResult(Response $response)
             }
 
             return $json;
-        } catch (\RuntimeException $e)
-        {
+        } catch (\RuntimeException $e) {
             throw new ApiException($e->getMessage());
         }
     }
 
-    public function addDivisionNumberToApiUrl()
+    /**
+     * @return mixed
+     */
+    private function getCurrentDivisionNumber()
     {
-        if (empty($this->division))
-        {
-            $me = new Me($this);
+        if (empty($this->division)) {
+            $me             = new Me($this);
             $this->division = $me->find()->CurrentDivision;
         }
 
-        $this->client()->setBaseUrl($this->apiUrl . '/' . $this->division);
+        return $this->division;
     }
 
     /**
@@ -240,6 +337,98 @@ public function getAccessToken()
         return $this->accessToken;
     }
 
+    private function acquireAccessToken()
+    {
+        // If refresh token not yet acquired, do token request
+        if (empty($this->refreshToken)) {
+            $body = [
+                'form_params' => [
+                    'redirect_uri' => $this->redirectUrl,
+                    'grant_type' => 'authorization_code',
+                    'client_id' => $this->exactClientId,
+                    'client_secret' => $this->exactClientSecret,
+                    'code' => $this->authorizationCode
+                ]
+            ];
+        } else { // else do refresh token request
+            $body = [
+                'form_params' => [
+                    'refresh_token' => $this->refreshToken,
+                    'grant_type' => 'refresh_token',
+                    'client_id' => $this->exactClientId,
+                    'client_secret' => $this->exactClientSecret,
+                ]
+            ];
+        }
+
+        $response = $this->client()->post($this->tokenUrl, $body);
+
+        if ($response->getStatusCode() == 200) {
+            $body = json_decode($response->getBody()->getContents(), true);
+
+            if (json_last_error() === JSON_ERROR_NONE) {
+                $this->accessToken  = $body['access_token'];
+                $this->refreshToken = $body['refresh_token'];
+                $this->tokenExpires = $this->getDateTimeFromExpires($body['expires_in']);
+            } else {
+                throw new ApiException('Could not acquire tokens, json decode failed. Got response: ' . $response->getBody()->getContents());
+            }
+        } else {
+            throw new ApiException('Could not acquire or refresh tokens');
+        }
+    }
+
+
+    private function getDateTimeFromExpires($expires)
+    {
+        if (!is_numeric($expires)) {
+            throw new \InvalidArgumentException('Function requires a numeric expires value');
+        }
+
+        return time() + 600;
+    }
+
+    /**
+     * @return mixed
+     */
+    public function getTokenExpires()
+    {
+        return $this->tokenExpires;
+    }
+
+    /**
+     * @param mixed $tokenExpires
+     */
+    public function setTokenExpires($tokenExpires)
+    {
+        $this->tokenExpires = $tokenExpires;
+    }
+
+    private function tokenHasExpired()
+    {
+        if (empty($this->tokenExpires)) {
+            return true;
+        }
+
+        return $this->tokenExpires <= time();
+    }
+
+    private function formatUrl($endPoint, $includeDivision = true)
+    {
+        if ($includeDivision) {
+            return implode('/', [
+                $this->apiUrl,
+                $this->getCurrentDivisionNumber(),
+                $endPoint
+            ]);
+        }
+
+        return implode('/', [
+            $this->apiUrl,
+            $endPoint
+        ]);
+    }
+
 
     /**
      * @return mixed