API limitation

I would like to know if it is possible with webservice/API from wordbee  to request only the newly created companies / Contacts ?

If we create customs fields in Wordbee, those fields are available for read / update through API in wordbee ?

And the last issue, how to trigger API in wordbee ? Is it possible for example, after each creation of a new company to trigger un webservice in wordbee ?

Thanks in advance