This API is used to Get Vendor List
Please check example usage of Vision Helpdesk API

Operation : view_vendor
Module : setting

$postfields["vis_module"] = "setting";
// This is the module under which you wish to perform operation

$postfields["vis_operation"] = "view_vendor";
// This is the operation field

Below is example API URL to fetch vendor list

XML: http://visiononlinedemo.com/support/api/index.php? vis_txtusername=admin &vis_txtuserpass=21232f297a57a5a743894a0e4a801fc3 &vis_module=setting
&vis_operation=view_vendor JSON: http://visiononlinedemo.com/support/api/index.php? vis_txtusername=admin &vis_txtuserpass=21232f297a57a5a743894a0e4a801fc3 &vis_module=setting
&vis_operation=view_vendor &vis_encode=json

OR use "access token" to fetch vendor list

XML: http://visiononlinedemo.com/support/api/index.php? vis_txttoken=WXprMk1UY3dZV1V6WWpZeU16RmpOelF3TVdReE5UWTJOVGMyTm1VeU4yUT0= &vis_module=setting
&vis_operation=view_vendor JSON http://visiononlinedemo.com/support/api/index.php? vis_txttoken=WXprMk1UY3dZV1V6WWpZeU16RmpOelF3TVdReE5UWTJOVGMyTm1VeU4yUT0= &vis_module=setting
&vis_operation=view_vendor &vis_encode=json