GET is only idempotent in terms of the effect of the client calling the server. The server is free to change the state of a resource at any time without inform

GET is only idempotent in terms of the effect of the client calling the server. The server is free to change the state of a resource at any time without informing the client. What a compliant server cannot do is change the state of a resource as a result of receiving the GET request from the client.