diff --git a/src/Conversation/Client.php b/src/Conversation/Client.php
index edc4a8e..7f1bd06 100644
--- a/src/Conversation/Client.php
+++ b/src/Conversation/Client.php
@@ -41,7 +41,7 @@ public function sendGeneralMessage($sender, $cid, $message)
      */
     public function sendCorporationMessage($params)
     {
-        return $this->client->post('topapi/message/corpconversation/asyncsend_v2', $params);
+        return $this->client->postJson('topapi/message/corpconversation/asyncsend_v2', $params);
     }
 
     /**
diff --git a/tests/Conversation/ClientTest.php b/tests/Conversation/ClientTest.php
index 0d9eeb7..68d50ce 100644
--- a/tests/Conversation/ClientTest.php
+++ b/tests/Conversation/ClientTest.php
@@ -32,7 +32,7 @@ public function sendCorporationMessage()
     {
         $this->make(Client::class)->sendCorporationMessage($params = ['foo' => 'bar'])
             ->assertPostUri('topapi/message/corpconversation/asyncsend_v2')
-            ->assertPostFormParams($params);
+            ->assertPostJson($params);
     }
 
     /** @test */