I'm integrating with an external system, they will be able to send a POST request through REST API and create records of a custom object I've created in my org. I need to send to the client the documentation about all the contracts, the endpoint and all the error or success messages related to this request. Is there a easy way in salesforce to get the json body they have to send me based on the needed fields? I would like to know if there is also a way to get all the other information like the curl, the error messages etc..
Thanks