I am interested if there is dedicated API endpoint for fetching custom fields for contact resources? It could be also endpoint that returns all available contact fields? Do you have sth like that?
Thanks in advance for help.
There is not an endpoint to pull all of the custom fields. They are not actually in place until you create them and they are named custom field 1 through 15 if created through the API. If they were created through the website they could have any name.
However; if you pull the endpoint for a contact it will show any field that has been filled out for that contact. This is not what you wanted, but it may be a work around. That endpoint can be found here. (http://developer.constantcontact.com/docs/contacts-api/contacts-resource.html)