The first thing you need to do to access the PayPal API is set up a developer account at PayPal Developer Central. It's simple, and best of all, it's free. There is a wealth of information on the Developer Central site, including:
Sample code provided by PayPal that demonstrates most of the API
A moderated forum where you can ask (and receive answers to) common or obscure API-related questions
The PayPal Sandbox [Hack #87], a test area in which you can run merchant transactions without using actual funds
PayPal Developer Central is located at https://developer.paypal.com. To create a developer account, click the registration link and enter basic information about yourself, such as your name, company, email address, as well as some optional profile questions.
When you're finished, you will be registered as a developer, at which point you'll be able to log into PayPal Developer Central, as shown in Figure 8-1.
Developer Central is divided into five areas:
Create test user accounts and test your code [Hack #87] .
Create and keep track of your SSL certificates [Hack #87] .
Manage pseudo-email messages sent from the Sandbox.
Ask questions and discuss the API with other developers in a user-to-user forum moderated by PayPal developers.
How-tos, sample code, and links to other forums (e.g., eBay and PayPal general forums).
Now that your developer account is set up, it's time to have some fun in the Sandbox.
?Rob Conery and Dave Nielsen