Web services allow programs to communicate over a network by calling methods on remote systems. They are frequently web APIs that can be accessed over a network like the internet. A web service call packages method and scoping information into an envelope that is transported across the network using defined protocols like HTTP and TCP. At the destination, the same protocols unpack the envelope and call the requested method. Web servers store web pages and dynamic content, and respond to client requests over the internet using HTTP to deliver HTML files and other objects.