From their site: Google Checkout is a checkout process that you integrate with your website, enabling your customers to buy from you quickly and securely, using a single username and password. Once they do, you can use Google Checkout to charge their credit cards, process their orders, and receive payment in your bank account.
The following is a list of libraries from ProgrammableWeb's Library Directory that matched your search term. Although there many different interpretations of the word "library" among software developers, ProgrammableWeb adheres to a specific definition so as to clearly distinguish libraries from SDKs and frameworks in a way that will facilitate clean search results. In ProgrammableWeb's parlance, the term "library" is strictly used to describe a platform-specific software tool that, when installed, results in the provisioning a specific API. Conversely, SDKs are exclusively for consuming APIs and Frameworks are agnostic to specific APIs. If you think a library, SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.