So I'm trying to call an external API using a Flow, so I added everything I needed to get the connection set: auth provider, named credential and external service. So far so good, connection is established, user is authenticated and api end point is reached.
My problem now is that I can't get the API schema in a way that the external action allows me to send individual parameters as the body of the request. I need to send an ID and a string, but because these are inside a json object, salesforce only shows me a "body" input, and nothing that I plug in there will work due to incompatible "types".
I've used online OpenAPI editors to try different ways to declare the body contents and format, and in Swagger everything looks fine.
This would probably be solved using an Apex class, but the purpose was to be able to depend on the Flow alone and not need Apex.
Any pointers or help is much appreciated