Currently, libyui-rest-api is designed to send parameters in URL not only for GET, but also for POST requests.
Though, according to W3:
POST is used to send data to a server to create/update a resource. The data sent to the server with POST is stored in the request body of the HTTP request
In order to make the API to be more consistent with the definition and purpose of POST request, please change all the POST requests to receive parameters in HTTP request body.