ARIA is business class management (ERP) software. It lets you manage inventory levels, maintain payroll, and process orders. It is written primarily in PHP and incorporates the ADODB database abstraction layer. There are currently translations for Chinese, Spanish, Italian, and French.
VitaleBay assists eBay sellers with managing their auctions. It automatically retrieves auction information and stores it in a PostgreSQL database, automatically emails the winning bidder with a "Congratulations" email, and stores bidder's information in database (name, address, payment method).
Fisterra is a GNOME development framework for implementing business management applications or ad hoc ERPs. Fisterra 2 is comprised of fisterra-base, a mature GNOME development framework, and fisterra-distribution, a vertical solution for the retail sector, with a beta POS (Point-Of-Sale). Its CORBA middleware allows the integration of Fisterra based applications with any other free or private systems.
Naina is a library to handle Secure Electronic Transactions (SET) protocol messages. It was shown to serve a well-known SET Wallet. It includes the source, protocol messages and wallet screenshots captured while testing, and a full certificates hierarchy generated for this test. The SET protocol was introduced for credit card payments in 1996. This protocol features electronic signatures for major messages, including merchant's offer and the order to buy. Please note that this protocol is not actively deployed since around 2003.
YourPay is a PHP class that can be used to submit WorldPay transactions through a WorldPay account without the very impersonal payment pages provided by the said company. This class will submit the user's credit card details in real-time and return either "Authorise" or "Decline" according to the response.