Hello Peter,

Yes to all your questions.
I’d like to forward you to the docs about this:
https://docs.thinkwisesoftware.com/docs/sf/process_flows#a-message-protocol-independent-web-service-in-a-process-flow
And also a example web service made with these functionalities:
 

I already created a custom protocol process flow endpoint, is it possible to setup the endpoint as public endpoint. If i use the public/iam/application/process_flow_name the process flow won't work. open/iam/application/proces_flow_name work with basic auth. We need a endpoint without basic auth to get header information and check ApiKey

the endpoint public/iam/application/subroutine_name works if parameters are set in body for example

{   "json_header" : { "apiKey" : 123456},

    "json_message" : {

    "currency": "EUR",

    "locationCode": "25546",

    "transportMethod": "Normal",

    "webshopOrderNumber": "FCF732T"

}

I already created a custom protocol process flow endpoint, is it possible to setup the endpoint as public endpoint?

This is supported. You can combine “open” and “public”. That should do the trick.