SOAP (Simple Object Access Protocol) and REST (Representational State Transfer) Web services are communication protocols .
REST through a single, consistent interface to access a named resource. Including the Internet open API, REST protocol most commonly used. SOAP is the application logic components as services, rather than data. It runs through different interfaces.
In brief, the REST data access, transfer and integration of the SOAP operation performed by more standardized message.
REST allows more types of data formats, more efficient and easy to use, and can only use the SOAP XML, SOAP over REST safer.