Using FairPay is quite easy. It installs and can be configured in a matter of minutes. After that, however, you need to program your business rules. Further, you need to test your business rules. This would ordinarily be a tedious process, were it not for PayPal's great testing facilities.

PayPal provides a "sandbox" area which lets you test everything except reversals (like chargebacks), and auctions. To utilise this resource, follow these steps:

1. Utilise the setting sandbox=on in your config file for FairPay.

2. Go to PayPal Developer Central and create an account there.

3. Enter the Sandbox area

4. Create a business account and attach a bank account to it. All financial information is pre-populated for testing purposes. No actual financial transactions ever take place in the Sandbox. Verify the bank account. Also make sure that you verify your account in general. You will have to use the Developer Central webmail interface to view the mail from any Sandbox accounts.

5. Create a personal account and attach a credit card. As above, just accept the pre-populated financial information.

6. Configure your Sandbox business account's IPN settings. Turn IPN on, and enter the URL for your copy of flipna.

7. Start testing. You can make buttons, use Send Money, etc. All transactions in buttons should be sent to www.sandbox.paypal.com in your buttons code as pertains to the webscr location within buttons.

8. When you're done testing, utilise sandbox=off in your config file for FairPay. Configure your final solution with buttons that will utilise the live PayPal site (at www.paypal.com for all webscr locations within the buttons).

Please note that flt_verified will be VERIFIED for Sandbox transaction IPN's tested against the Sandbox. However, you cannot test Sandbox transaction IPN's against the live system, nor can you test live IPN's against the Sandbox. They are mutually exclusive. If you must test new modules while live ones remain in production, it is recommended that you utilise a second copy of FairPay in another location. This can be done by reinstalling to different locations on the same system using a different location for the fairpay directory and a different cgi-bin directory for flipna). In this manner, you can have one configuration for testing, and one for live use. This falls within acceptable use within the FairPay license.