Obtain API Access for PayPal
Â
Obtain API Access for Express Checkout or PayPal Pro
(Requires a PayPal business account)
1. Log in to your PayPal account:
  From My Account screen click Profile.                      Â
Â
From My Profile Screen click My Setting Tools.
Locate API Access and click "Update".
On the API Access screen, click View API Signature under Option 2.
On the View or Remove API Signature screen, copy your API Username, Password and Signature
into a text editor (wordpad, etc.) for later use. Click the "Done" button when finished.