The 4 field types are: text/string, number, color code (which I guess could be text), image. The code has a true/false option but that isn't necessary to use for my purpose.
It's an image API so all the fields are attributes of one image. It's a multilevel array of attributes.
Here's a short example of the JSON. Any one image would have a random number of attributes/key pairs.
{
"template_name": "Facebook-Post-1200x900",
"api_key": "XXXXXXXXXXXXXX",
"modifications": [
{
"name": "background-image",
"image_url": "default",
"width": "1270.59px",
"height": "900px",
"visible": "true"
},
{
"name": "shape-0",
"type": "shape",
"background-color": "black",
"border-color": "initial",
"border-width": "initial",
"visible": "true"
},