What are main differences between API and Web Service?

Question

What are main differences between API and Web Service?

Answer

All Web services are APIs but not all APIs are Web services. Web services might not contain all the specifications and cannot perform all the tasks that APIs would perform. A Web service uses only three styles of use: SOAP, REST and XML-RPC for communication whereas API may be exposed to in multiple ways. A Web service always needs a network to operate while APIs don’t need a network for operation.