Get JSON type

Let’s say I have fetched this JSON from an API (server side):

{
id: "38eced94-df59-4e26-bb6e-c6e6938dd00e"
customer_reference: "Order 72"
amount_delivered: 0
amount_reserved: 27
amount_total: 29
}

And what I want to get from this JSON is the field type:

{
id: string
customer_reference: string
amount_delivered: integer
amount_reserved: integer
amount_total: integer
}

Is this somehow possible in Wappler on the server-side? I think the PHP function is gettype, but I don’t see anything similar in the visual tools in Wappler. Or is there a way how I can apply this PHP function server-side?

https://www.php.net/manual/en/function.gettype.php