PayPal - Creating an API Signature
An API signature consists of an API user-name along with an associated API password and signature, all of which are assigned by PayPal. You need to include this information whenever you execute a PayPal API operation. Follow the steps below to create an API signature:
Log in to PayPal, then under Selling Tools (on the left), click on Seller preferences:
On the next page, locate the row begining with API Access and click on Update.
On the next page, scroll down to find the NVP/SOAP API intergration (Classic) and either click on the Request API signature (and then agree to the terms) or if you already have a signature set up, click on Manage API Credentials.
Afer agreeing to the terms, the on final page, click on Show to dispaly your credentials in turn. Click on Done when finished, having taken note of your credentials.
PayPal provides API access to Business and Premier accounts only and NOT Personal accounts.
Upgrading from a Personal to a Premier PayPal account entails verifying your bank details.