A SOAP message contains the following sections:

SOAP envelope

The envelope defines the framework of the message, the content of the message, and what should handle the message.

SOAP header

The header identifies the entity that sent the SOAP message. It includes authentication information. It also includes information about how to process the SOAP message.

SOAP body

The body is the container for the data that the client and web service provider pass between each other.

SOAP messages are XML. When a SOAP message contains multiple-occurring elements, the groups of elements form levels in the XML hierarchy. The groups are related when one level is nested within another.

A SOAP request message can contain hierarchical data. For example, the client sends a request to add customer orders to a sales database. The client passes two groups of data in a SOAP request message. One group contains a customer ID and name, and the other group contains order information. The order information occurs multiple times.

A SOAP response message can contain hierarchical data. For example, a web service client generates a SOAP request for customer orders. The web service returns an order header and multiple-occurring order detail elements in the SOAP response.