Both Amazon and eBay (along with a number of other retailers) have APIs that allow developers to sell products by listing them using an API.
Amazon's Marketplace Web Service (Amazon MWS) allows sellers to list items for sale on the Amazon marketplace through an API. By using this, we could automate the process of listing products we have in our own e-commerce store, on the Amazon marketplace website. This would extend opportunities for new customers to do business with us. By suitably integrating the API with our framework, we could:
Automatically list our products on Amazon marketplace
Automatically remove our products from Amazon marketplace when stock levels are low
A PHP client library is available for the Amazon MWS API, which can be used to integrate with our framework: http://mws.amazon.com/phpClientLibrary.html.
eBay has a developer center for various languages and APIs, including searching, managing feedback, and of course, creating listings. With this API we could:
Automatically create listings based on new products
Automatically create repeat listings for existing products that are still in stock (perhaps, generating new ones each week)
Automatically post good feedback to the buyer once the order is complete
A number of PHP resources are available for working with the API, including ones specific for their trading API, which would be of most use to us. Some of these include: