The JSON data format uses the field name string as the attribute name, you can use a "naming" parameter to specify that you would like to use field id as the attribute name to identify a field.
Possible values include: EID (Field Id), FNAME (Field Name). This type of attribute will only need to be set once, and the configuration will be applied to all subsequent requests in this session.
curl --get -d "naming=EID" \ -H "Authorization:Basic YOUR_API_KEY_GOES_HERE" \ -d api \ https://www.ragic.com/demo/sales/1