REST API/Webhooks upport with Adobe Sign for Small Business

Dear Community, 

I was not able to find a clear answer. to my question Also the contact of the live support was not succesful.

Is my Adobe Sign for Small Business Plan supporting API and Webhooks?

If yes, is it possible to access the REST API or Webhooks via my native app? Or do I have to create an Developer Account and go trough the "partner" program?

Thank you very much for your support.

best regards

Florian