It would be very useful to have an API call
to edit a generic custom field (that could be sent to every client upon request).
I.E: If my client answers a survey for the current price of a product, an automation task
would sent a message with the content of the custom field "current.price.product".
same way we can send back to the client the content of a custom field that he/she has.
trough the API I would update this field every day.