Plain Old XML (POX) refers to techniques where applications exchange raw XML documents using standard transfer protocols, such as HTTP, Simple Mail Transfer Protocol (SMTP) and File Transfer Protocol (FTP), or using proprietary protocols (such as message-oriented middleware). “Raw” means that XML documents aren’t wrapped in any kind of messaging protocol or envelope, such as SOAP or AtomPub. Instead, POX relies on packaging capabilities of the transfer protocol and out-of-band agreements to supply infrastructure information and all metadata about payload formats and service interface descriptions. Those trade-offs aside, POX supports exceptional interoperability. It provides significantly less infrastructure functionality than other XML messaging systems, such as a message envelope, and, therefore, imposes additional burdens on applications to perform infrastructure functionality.