Amazon on Tuesday launched hosted e-commerce payment services for merchants who want to outsource all or some of their online transaction processing tasks.

The two new offerings, called Checkout By Amazon and Amazon Simple Pay, are the latest services for businesses introduced by Amazon, which is best known for its massive online retailing operation.

The products join a crowded and diverse market for online payment services, which includes providers like eBay's PayPal as well as Google with its Google Checkout.

Checkout By Amazon is described by the company as a "complete checkout solution" equal to the one Amazon provides at its own online store.

Among its features are Amazon's 1-Click functionality, as well as tools for managing shipping charges, sales tax, promotions, refunds, cancellations and chargebacks.

Merchants can also let buyers access their Amazon.com account information to complete their purchases, as well as extend to buyers the protection of Amazon's "A to Z" transaction guarantee.

On the other hand, Amazon Simple Pay provides a number of payment products and allows customers to access Amazon.com account information on the participating merchant's Web site.

Simple Pay doesn't include the broad transaction-processing features of Checkout By Amazon, like the real-time shipping- and tax-calculation and order-management features.

"If you don't need Amazon's end-to-end checkout pipeline and order management capabilities, but still want to enable your customers to use their payment information already on file at Amazon.com, use Amazon Simple Pay," reads the Simple Pay information page.

In this page, merchants can compare the two products.

The fee structure for both products is the same. For transactions of US$10 and up, merchants pay 2.9 percent of the amount plus $0.30. Amazon will lower the commission percentage if the merchant hits certain levels of monthly payment volume. The fee for transactions lower than $10 is 5 percent of the amount plus $0.05.