Next to our regular API we also offer the use of EPP! Using EPP allows you to implement our domain registration systems very quick if you already have an existing EPP enviroment.
You can find more information about our EPP interface right here: https://doc.openprovider.eu/index.php/EPP_Index#Introduction
Please note that you can only order and manage domain names using EPP. SSL, Plesk and SpamExperts are only implemented into the general API. This is because EPP is specifically made for domain names.