diff --git a/README.md b/README.md
index abff0ea..a88ab91 100644
--- a/README.md
+++ b/README.md
@@ -141,6 +141,7 @@ echo $curl->responseHeaders['CoNTeNT-TyPE'] . "\n"; // image/png
 ```
 
 ```php
+// Clean up.
 $curl->close();
 ```
 
@@ -222,7 +223,7 @@ Curl::setCookieFile($cookie_file)
 Curl::setCookieJar($cookie_jar)
 Curl::setCookieString($string)
 Curl::setCookies($cookies)
-Curl::setDefaultDecoder($decoder = 'json')
+Curl::setDefaultDecoder($mixed = 'json')
 Curl::setDefaultJsonDecoder()
 Curl::setDefaultTimeout()
 Curl::setDefaultUserAgent()
@@ -230,7 +231,7 @@ Curl::setDefaultXmlDecoder()
 Curl::setDigestAuthentication($username, $password = '')
 Curl::setHeader($key, $value)
 Curl::setHeaders($headers)
-Curl::setJsonDecoder($function)
+Curl::setJsonDecoder($mixed)
 Curl::setMaxFilesize($bytes)
 Curl::setOpt($option, $value)
 Curl::setOpts($options)
@@ -240,7 +241,7 @@ Curl::setReferrer($referrer)
 Curl::setTimeout($seconds)
 Curl::setUrl($url, $mixed_data = '')
 Curl::setUserAgent($user_agent)
-Curl::setXmlDecoder($function)
+Curl::setXmlDecoder($mixed)
 Curl::success($callback)
 Curl::unsetHeader($key)
 Curl::verbose($on = true, $output = STDERR)
@@ -273,7 +274,7 @@ MultiCurl::setCookies($cookies)
 MultiCurl::setDigestAuthentication($username, $password = '')
 MultiCurl::setHeader($key, $value)
 MultiCurl::setHeaders($headers)
-MultiCurl::setJsonDecoder($function)
+MultiCurl::setJsonDecoder($mixed)
 MultiCurl::setOpt($option, $value)
 MultiCurl::setOpts($options)
 MultiCurl::setPort($port)
@@ -282,7 +283,7 @@ MultiCurl::setReferrer($referrer)
 MultiCurl::setTimeout($seconds)
 MultiCurl::setUrl($url)
 MultiCurl::setUserAgent($user_agent)
-MultiCurl::setXmlDecoder($function)
+MultiCurl::setXmlDecoder($mixed)
 MultiCurl::start()
 MultiCurl::success($callback)
 MultiCurl::unsetHeader($key)
diff --git a/src/Curl/Curl.php b/src/Curl/Curl.php
index 82d194c..fc65aad 100644
--- a/src/Curl/Curl.php
+++ b/src/Curl/Curl.php
@@ -905,16 +905,18 @@ class Curl
      * Set Default Decoder
      *
      * @access public
-     * @param  $decoder string|callable
+     * @param  $mixed boolean|callable|string
      */
-    public function setDefaultDecoder($decoder = 'json')
+    public function setDefaultDecoder($mixed = 'json')
     {
-        if (is_callable($decoder)) {
-            $this->defaultDecoder = $decoder;
+        if ($mixed === false) {
+            $this->defaultDecoder = false;
+        } elseif (is_callable($mixed)) {
+            $this->defaultDecoder = $mixed;
         } else {
-            if ($decoder === 'json') {
+            if ($mixed === 'json') {
                 $this->defaultDecoder = $this->jsonDecoder;
-            } elseif ($decoder === 'xml') {
+            } elseif ($mixed === 'xml') {
                 $this->defaultDecoder = $this->xmlDecoder;
             }
         }
@@ -988,13 +990,16 @@ class Curl
      * Set JSON Decoder
      *
      * @access public
-     * @param  $function
+     * @param  $mixed boolean|callable
      */
-    public function setJsonDecoder($function)
+    public function setJsonDecoder($mixed)
     {
-        if (is_callable($function)) {
-            $this->jsonDecoder = $function;
-            $this->jsonDecoderArgs = func_get_args();
+        if ($mixed === false) {
+            $this->jsonDecoder = false;
+            $this->jsonDecoderArgs = array();
+        } elseif (is_callable($mixed)) {
+            $this->jsonDecoder = $mixed;
+            $this->jsonDecoderArgs = array();
         }
     }
 
@@ -1002,12 +1007,14 @@ class Curl
      * Set XML Decoder
      *
      * @access public
-     * @param  $function
+     * @param  $mixed boolean|callable
      */
-    public function setXmlDecoder($function)
+    public function setXmlDecoder($mixed)
     {
-        if (is_callable($function)) {
-            $this->xmlDecoder = $function;
+        if ($mixed === false) {
+            $this->xmlDecoder = false;
+        } elseif (is_callable($mixed)) {
+            $this->xmlDecoder = $mixed;
         }
     }
 
@@ -1322,21 +1329,18 @@ class Curl
         $response = $raw_response;
         if (isset($response_headers['Content-Type'])) {
             if (preg_match($this->jsonPattern, $response_headers['Content-Type'])) {
-                $json_decoder = $this->jsonDecoder;
                 if ($this->jsonDecoder) {
                     $args = $this->jsonDecoderArgs;
                     array_unshift($args, $response);
-                    $response = call_user_func_array($json_decoder, $args);
+                    $response = call_user_func_array($this->jsonDecoder, $args);
                 }
             } elseif (preg_match($this->xmlPattern, $response_headers['Content-Type'])) {
-                $xml_decoder = $this->xmlDecoder;
-                if ($xml_decoder) {
-                    $response = call_user_func($xml_decoder, $response);
+                if ($this->xmlDecoder) {
+                    $response = call_user_func($this->xmlDecoder, $response);
                 }
             } else {
-                $default_decoder = $this->defaultDecoder;
-                if ($default_decoder) {
-                    $response = call_user_func($default_decoder, $response);
+                if ($this->defaultDecoder) {
+                    $response = call_user_func($this->defaultDecoder, $response);
                 }
             }
         }
diff --git a/src/Curl/MultiCurl.php b/src/Curl/MultiCurl.php
index b70b695..fad346f 100644
--- a/src/Curl/MultiCurl.php
+++ b/src/Curl/MultiCurl.php
@@ -514,12 +514,14 @@ class MultiCurl
      * Set JSON Decoder
      *
      * @access public
-     * @param  $function
+     * @param  $mixed boolean|callable
      */
-    public function setJsonDecoder($function)
+    public function setJsonDecoder($mixed)
     {
-        if (is_callable($function)) {
-            $this->jsonDecoder = $function;
+        if ($mixed === false) {
+            $this->jsonDecoder = false;
+        } elseif (is_callable($mixed)) {
+            $this->jsonDecoder = $mixed;
         }
     }
 
@@ -527,12 +529,14 @@ class MultiCurl
      * Set XML Decoder
      *
      * @access public
-     * @param  $function
+     * @param  $mixed boolean|callable
      */
-    public function setXmlDecoder($function)
+    public function setXmlDecoder($mixed)
     {
-        if (is_callable($function)) {
-            $this->xmlDecoder = $function;
+        if ($mixed === false) {
+            $this->xmlDecoder = false;
+        } elseif (is_callable($mixed)) {
+            $this->xmlDecoder = $mixed;
         }
     }
 
diff --git a/tests/PHPCurlClass/PHPCurlClassTest.php b/tests/PHPCurlClass/PHPCurlClassTest.php
index 77e4101..4786ecd 100644
--- a/tests/PHPCurlClass/PHPCurlClassTest.php
+++ b/tests/PHPCurlClass/PHPCurlClassTest.php
@@ -1417,6 +1417,11 @@ class CurlTest extends \PHPUnit\Framework\TestCase
         $test->server('json_response', 'POST', $data);
         $this->assertFalse(is_object($test->curl->response));
         $this->assertTrue(is_array($test->curl->response));
+
+        $test = new Test();
+        $test->curl->setJsonDecoder(false);
+        $test->server('json_response', 'POST', $data);
+        $this->assertTrue(is_string($test->curl->response));
     }
 
     public function testJsonContentTypeDetection()
@@ -2588,7 +2593,7 @@ class CurlTest extends \PHPUnit\Framework\TestCase
                     'value' => $value,
                 ));
 
-                $this->assertInstanceOf('SimpleXMLElement', $test->curl->response);
+                $this->assertInstanceOf(SimpleXMLElement::class, $test->curl->response);
 
                 $doc = new DOMDocument();
                 $doc->formatOutput = true;
@@ -2947,21 +2952,69 @@ class CurlTest extends \PHPUnit\Framework\TestCase
 
     public function testXMLDecoder()
     {
-        $data = array(
-            'key' => 'Content-Type',
-            'value' => 'text/xml',
-        );
-
         $test = new Test();
-        $test->server('xml_with_cdata_response', 'POST', $data);
+        $test->server('xml_with_cdata_response', 'POST');
+        $this->assertTrue(is_object($test->curl->response));
+        $this->assertInstanceOf(SimpleXMLElement::class, $test->curl->response);
         $this->assertFalse(strpos($test->curl->response->saveXML(), '<![CDATA[') === false);
 
         $test = new Test();
         $test->curl->setXmlDecoder(function ($response) {
             return simplexml_load_string($response, 'SimpleXMLElement', LIBXML_NOCDATA);
         });
-        $test->server('xml_with_cdata_response', 'POST', $data);
+        $test->server('xml_with_cdata_response', 'POST');
+        $this->assertTrue(is_object($test->curl->response));
+        $this->assertInstanceOf(SimpleXMLElement::class, $test->curl->response);
         $this->assertTrue(strpos($test->curl->response->saveXML(), '<![CDATA[') === false);
+
+        $test = new Test();
+        $test->curl->setXmlDecoder(false);
+        $test->server('xml_with_cdata_response', 'POST');
+        $this->assertTrue(is_string($test->curl->response));
+    }
+
+    public function testDefaultDecoder()
+    {
+        // Default.
+        $test = new Test();
+        $test->server('download_file_size', 'GET');
+        $this->assertTrue(is_string($test->curl->response));
+
+        // Callable.
+        $test = new Test();
+        $test->curl->setDefaultDecoder(function ($response) {
+            return '123';
+        });
+        $test->server('download_file_size', 'GET');
+        $this->assertEquals('123', $test->curl->response);
+
+        // "json".
+        $test = new Test();
+        $test->curl->setDefaultDecoder('json');
+        $test->server('json_response', 'POST', array(
+            'key' => 'Content-Type',
+            'value' => 'application/but-not-json',
+        ));
+        $this->assertInstanceOf(stdClass::class, $test->curl->response);
+
+        // "xml".
+        $test = new Test();
+        $test->curl->setDefaultDecoder('xml');
+        $test->server('xml_response', 'POST', array(
+            'key' => 'Content-Type',
+            'value' => 'text/but-not-xml',
+        ));
+        $this->assertInstanceOf(SimpleXMLElement::class, $test->curl->response);
+
+        // False.
+        $test = new Test();
+        $test->curl->setDefaultDecoder('json');
+        $test->curl->setDefaultDecoder(false);
+        $test->server('json_response', 'POST', array(
+            'key' => 'Content-Type',
+            'value' => 'application/but-not-json',
+        ));
+        $this->assertTrue(is_string($test->curl->response));
     }
 
     public function testTotalTime()
diff --git a/tests/PHPCurlClass/PHPMultiCurlClassTest.php b/tests/PHPCurlClass/PHPMultiCurlClassTest.php
index b884396..c7f832b 100644
--- a/tests/PHPCurlClass/PHPMultiCurlClassTest.php
+++ b/tests/PHPCurlClass/PHPMultiCurlClassTest.php
@@ -2079,8 +2079,40 @@ class MultiCurlTest extends \PHPUnit\Framework\TestCase
         $this->assertEquals('yummy', $get_2->responseCookies['mycookie']);
     }
 
-    public function testJSONDecoder()
+    public function testJsonDecoder()
     {
+        $data = array(
+            'key' => 'Content-Type',
+            'value' => 'application/json',
+        );
+
+        $multi_curl = new MultiCurl();
+        $multi_curl->setHeader('X-DEBUG-TEST', 'json_response');
+
+        $post_1 = $multi_curl->addPost(Test::TEST_URL, $data);
+        $post_1->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_object($instance->response));
+            \PHPUnit\Framework\Assert::assertFalse(is_array($instance->response));
+        });
+
+        $post_2 = $multi_curl->addPost(Test::TEST_URL, $data);
+        $post_2->setJsonDecoder(function ($response) {
+            return json_decode($response, true);
+        });
+        $post_2->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertFalse(is_object($instance->response));
+            \PHPUnit\Framework\Assert::assertTrue(is_array($instance->response));
+        });
+
+        $post_3 = $multi_curl->addPost(Test::TEST_URL, $data);
+        $post_3->setJsonDecoder(false);
+        $post_3->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_string($instance->response));
+        });
+
+        $multi_curl->start();
+
+
         $multi_curl = new MultiCurl();
         $multi_curl->setHeader('X-DEBUG-TEST', 'json_response');
         $multi_curl->setJsonDecoder(function ($response) {
@@ -2089,7 +2121,6 @@ class MultiCurlTest extends \PHPUnit\Framework\TestCase
 
         $get_1 = $multi_curl->addGet(Test::TEST_URL);
         $get_1->complete(function ($instance) {
-            \PHPUnit\Framework\Assert::assertInstanceOf('Curl\Curl', $instance);
             \PHPUnit\Framework\Assert::assertEquals('foo', $instance->response);
         });
 
@@ -2100,17 +2131,65 @@ class MultiCurlTest extends \PHPUnit\Framework\TestCase
             });
         });
         $get_2->complete(function ($instance) {
-            \PHPUnit\Framework\Assert::assertInstanceOf('Curl\Curl', $instance);
             \PHPUnit\Framework\Assert::assertEquals('bar', $instance->response);
         });
 
+        $get_3 = $multi_curl->addGet(Test::TEST_URL);
+        $get_3->beforeSend(function ($instance) {
+            $instance->setJsonDecoder(false);
+        });
+        $get_3->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_string($instance->response));
+        });
+
         $multi_curl->start();
         $this->assertEquals('foo', $get_1->response);
         $this->assertEquals('bar', $get_2->response);
+
+
+        $multi_curl = new MultiCurl();
+        $multi_curl->setHeader('X-DEBUG-TEST', 'json_response');
+        $multi_curl->setJsonDecoder(false);
+
+        $get_4 = $multi_curl->addGet(Test::TEST_URL);
+        $get_4->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_string($instance->response));
+        });
+
+        $multi_curl->start();
     }
 
     public function testXMLDecoder()
     {
+        $multi_curl = new MultiCurl();
+        $multi_curl->setHeader('X-DEBUG-TEST', 'xml_with_cdata_response');
+
+        $post_1 = $multi_curl->addPost(Test::TEST_URL);
+        $post_1->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_object($instance->response));
+            \PHPUnit\Framework\Assert::assertInstanceOf(SimpleXMLElement::class, $instance->response);
+            \PHPUnit\Framework\Assert::assertFalse(strpos($instance->response->saveXML(), '<![CDATA[') === false);
+        });
+
+        $post_2 = $multi_curl->addPost(Test::TEST_URL);
+        $post_2->setXmlDecoder(function ($response) {
+            return simplexml_load_string($response, 'SimpleXMLElement', LIBXML_NOCDATA);
+        });
+        $post_2->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_object($instance->response));
+            \PHPUnit\Framework\Assert::assertInstanceOf(SimpleXMLElement::class, $instance->response);
+            \PHPUnit\Framework\Assert::assertTrue(strpos($instance->response->saveXML(), '<![CDATA[') === false);
+        });
+
+        $post_3 = $multi_curl->addPost(Test::TEST_URL);
+        $post_3->setXmlDecoder(false);
+        $post_3->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_string($instance->response));
+        });
+
+        $multi_curl->start();
+
+
         $multi_curl = new MultiCurl();
         $multi_curl->setHeader('X-DEBUG-TEST', 'xml_with_cdata_response');
         $multi_curl->setXmlDecoder(function ($response) {
@@ -2119,7 +2198,6 @@ class MultiCurlTest extends \PHPUnit\Framework\TestCase
 
         $get_1 = $multi_curl->addGet(Test::TEST_URL);
         $get_1->complete(function ($instance) {
-            \PHPUnit\Framework\Assert::assertInstanceOf('Curl\Curl', $instance);
             \PHPUnit\Framework\Assert::assertEquals('foo', $instance->response);
         });
 
@@ -2130,13 +2208,32 @@ class MultiCurlTest extends \PHPUnit\Framework\TestCase
             });
         });
         $get_2->complete(function ($instance) {
-            \PHPUnit\Framework\Assert::assertInstanceOf('Curl\Curl', $instance);
             \PHPUnit\Framework\Assert::assertEquals('bar', $instance->response);
         });
 
+        $get_3 = $multi_curl->addGet(Test::TEST_URL);
+        $get_3->beforeSend(function ($instance) {
+            $instance->setXmlDecoder(false);
+        });
+        $get_3->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_string($instance->response));
+        });
+
         $multi_curl->start();
         $this->assertEquals('foo', $get_1->response);
         $this->assertEquals('bar', $get_2->response);
+
+
+        $multi_curl = new MultiCurl();
+        $multi_curl->setHeader('X-DEBUG-TEST', 'xml_with_cdata_response');
+        $multi_curl->setXmlDecoder(false);
+
+        $get_4 = $multi_curl->addGet(Test::TEST_URL);
+        $get_4->complete(function ($instance) {
+            \PHPUnit\Framework\Assert::assertTrue(is_string($instance->response));
+        });
+
+        $multi_curl->start();
     }
 
     public function testDownloadCallback()
diff --git a/tests/PHPCurlClass/server.php b/tests/PHPCurlClass/server.php
index 5977eb6..78442c5 100644
--- a/tests/PHPCurlClass/server.php
+++ b/tests/PHPCurlClass/server.php
@@ -253,7 +253,7 @@ if ($test === 'http_basic_auth') {
     readfile($unsafe_file_path);
     exit;
 } elseif ($test === 'download_file_size') {
-    $bytes = $_GET['bytes'];
+    $bytes = isset($_GET['bytes']) ? $_GET['bytes'] : 1234;
     $str = str_repeat('.', $bytes);
     header('Content-Type: application/octet-stream');
     header('Content-Length: ' . strlen($str));