XML-RPC is a protocol that uses XML messages to perform Remote Procedure Calls. Requests are encoded in XML and sent via HTTP POST; XML responses are embedded in the body of the HTTP response.

More succinctly, XML-RPC = HTTP + XML + Remote Procedure Calls.

Because XML-RPC is platform independent, diverse applications can communicate with one another. For example, a Java client can speak XML-RPC to a Perl server.

To get a quick sense of XML-RPC, here is a sample XML-RPC request to a weather service (with the HTTP Headers omitted):

<?xml version="1.0" encoding="ISO-8859-1"?>

<methodCall>

<methodName>weather.getWeather</methodName>

<params>

<param><value>10016</value></param>

</params>

</methodCall>

The request consists of a simple element, which specifies the method name (getWeather) and any method parameters (zip code).