What data format do Web Service Callouts typically use for communication?

Web Service Callouts commonly use XML as the preferred data format for communication. XML, or Extensible Markup Language, is structured and allows for a standardized way to encode a document in a format that is both human-readable and machine-readable. It provides a way to define complex data structures, making it suitable for describing the data and its relationships in a clear manner.

Many web services, especially those that adhere to the SOAP (Simple Object Access Protocol) standard, inherently use XML to transmit data. The capability of XML to handle nested data structures and attributes makes it advantageous in environments where complexity and hierarchy of data representation are significant.

While JSON has gained popularity in recent years for web APIs, particularly in RESTful services, the emphasis in this context is on traditional web services where XML remains the standard. CSV and Plain Text, on the other hand, do not provide the structured context needed for complex data exchanges in the same way that XML does.

Thus, XML as the data format for Web Service Callouts maintains compatibility with established standards and practices in web service communication.