Why SOAP services are not cacheable in Salesforce?

Hi,

To add more -

REST does not prescribe any particular mechanism for how to encode request parameters in the URL. What is recommended is that clients never do any URL synthesis: let the server do all the URL creation (by whatever mechanism you want, such as embedding within the path or as query parameters). What you definitely shouldn't do is have a GET where the client sends a body to the server! Any cache is likely to lose that. Instead, when that request doesn't correspond to a simple fetch of some resource, you POST or PUT that complex document to the server and GET the result of the operation as a separate stage.

Hope it helps.