diff --git a/lib/curl.php b/lib/curl.php
index 9d9497f..b25b765 100644
--- a/lib/curl.php
+++ b/lib/curl.php
@@ -168,7 +168,23 @@ function put($url, $vars = array()) {
     function request($method, $url, $vars = array()) {
         $this->error = '';
         $this->request = curl_init();
-        if (is_array($vars)) $vars = http_build_query($vars, '', '&');
+
+        $json_payload = '';
+        if (strtolower($method) != 'get') {
+            foreach ($this->headers as $key => $value) {
+                if (strtolower($value) == 'application/json') {
+                    $json_payload = json_encode($vars);
+                }
+            }
+        }
+
+        if (is_array($vars)) {
+            if ($json_payload == '') {
+                $vars = http_build_query($vars, '', '&');
+            }else {
+                $vars = $json_payload;
+            }
+        }
         
         $this->set_request_method($method);
         $this->set_request_options($url, $vars);