It is an XML-based messaging protocol for exchanging information among computers
It is an extension to HTTP protocol for XML messaging.
It only works with XML and hence needs more bandwidth compared to REST
SOAP is platform- and language-independent.
Although SOAP can be used in a variety of messaging systems and can be delivered via a variety of transport protocols, the initial focus of SOAP is remote procedure calls transported via HTTP.
SOAP supports both stateful and stateless operations
It is functional-driven, means that data here is available as services, eg, getUser