Add subscriber with custom fields by API

@JAMJA - can you please show me a screenshot with the code that does the api call and also the field in the web api interface? (the field from custom fields area)
Hi @twisted1919,it work now, my miss take is not upper case custom field in API code. Thanks
Is it now possible to create custom fields through the API? If not, do the custom fields need to be created for each list prior to adding records through the API, or is there a more efficient way to get the same custom fields for every list for a customer?
So if we create a list through the API, we have to create the custom fields for that list manually before sending the subscribers via API, or manually upload the list as a csv file to automatically create the fields? Is this by design?