Hello Saiyam,
Check status can be used in two areas;
- The callback URL - This is the immediate page called after a payment is made. I,e the return URL after payments have been processed.
- The IPN - Instant payment notification. The URL PesaPal calls whenever there is a status change. Technically, the client will never view the contents of this page. It’s a background process used to update your system.
When checking the status, you need the merchant reference and the PesaPal tracking ID (the tracking ID is not necessary when using the checkStatusByMerchantRef API). When PesaPal executes the two links above, it appends the reference and tracking ID on both URLs. However, the two links differ in two ways.
- The callback URL does not have the notification type variable appended on it. The notification type will only be available on the IPN URL.
- The IPN needs some commands instructing PesaPal to terminate further IPN call in regards to a certain transaction. You need to echo some JSON code and exit your system. The JSON code should be the only data echoed on the IPN URL. If you include any another additional data PesaPal will not ready the JSON hence the IPN will run over and over.
Have a look at this PHP example:
developer.pesapal.com/forum/2-pesapal-in...-pesapal-php-example 
