In this tip, learn about the different solutions available for passing binary data (typically files) to a Web service. The evolution of Web service protocols has gone from supporting very simple requests with simple parameters to fully supporting modern, object-oriented languages. XML-RPC, arguably one of the earliest forms of Web services, only supported simple types -- strings, integers, booleans, and the like. SOAP took this one step further with its encoding rules for objects. The last step -- improving on the binary -- came with SOAP with attachments. SOAP with attachments was originally introduced as an extension to SOAP 1.1, and it is supported by the major SOAP kits. Although SOAP 1.2, the official W3C release, does not support attachments yet, work is under way to include them in the (ideally) near future.