Can i create Custom defined Functions that will make calls to an API, after a successful call the received data will populate into a data-ease form?

Hi Blessed.

The best way to do this would be to use the Remote() function.

This was introduced in 8.5 and will be much enhanced in 9.

You can with this query any HTTP accessible API and use the data in your form.

You can also create a CDF but it is somewhat of a dark art these days.

What API are you trying to connect to?

REST API