I'm testing my PayPal's accounts with SandBox, I read that after PayPal answer I should send a post request with my transaction id, but I don´t understand why. When PayPal send's me request with GET, mi account show operation complete, so:
1.- Why I need send a post request with confirmation if PayPal already done the transaction?
2.- Why I need a Identity token if PayPal already done the transaction?
Thanks.