Mautic Community Forums

Can I add options in Lookup or Select multiple type custom field "on the go" through API or tracking pixel?

I am using lookup and select multiple data types for custom field.
My problem with both these types is that i have to add pre-defined options in them
Is there any way I can add options on the go (impromptu) using API or tracking pixel?
Because I don’t know all the options beforehand.