Hello Michael Cruden. I had the same question as you but I think I managed to understand it from this other page here:

\"...custom data types as a way to store multiple variables (which can be of the same or different data types) within a single variable.\"
Custom Data Types, Advantages of using Custom Data Type, Creating Custom Data Type and Using Custom Data Type in Flutterflow (https://docs.flutterflow.io/data-and-backend/custom-data-types#creating-custom-data-type)

Maybe my reasoning is too simplistic but I found it very similar to the relationship between SQL and NoSQL (used precisely by Firebase).

JSON and traditional SQL verticalize the process too much, making the search more complex and time-consuming and consuming much more machine resources. With this strategy of Custom Data Types in JSON we do like NoSQL by offering other documents within documents (😂 😂) optimizing that we don't have to remodel old data, just \"makeup\" it.

\"This flexibility allows some entries to have a few keys and other entries to have completely different sets of keys. For example, one entry may have the keys “name,” “rank,” and “serial number,” while another could store just the “name,” and a third might hold “name,” “age,” “home town,” and “height.” This flexibility is a blessing and a curse for developers. Adding special fields for particular rows is simple.\"
at What is a NoSQL database? (https://venturebeat.com/business/what-is-a-nosql-database/)

Could that be it or am I mistaken?

Maybe for it to work correctly you need to list this Type as Anything precisely because it contains varied data, I've never tried. and two [ [ \"...\",] ,] not just the quotes Michael Cruden . Because in my opinion it is a list within a list. As I have never tried this, this leads me to think that the call API created also has to be exclusive to its result.

API Parse as DataType option