Web Service
1. The format of the data is based on the SOAP protocol
2. Data transmission only supports HTTP protocol
3. It can only be deployed on IIS
WCF
1. The format of the data is based on the SOAP protocol
2. Data transmission supports HTTP, HTTPS, TCP, Named Pipes, MSMQ
3, can be deployed in applications, IIS or Windows services
webApi
1. The format of the data is relatively free, which can be json, xml and user-defined
2. Data transmission supports HTTP and HTTPS protocols
3. It can be deployed on other Host/Server servers such as IIS