API for sage 100

Hi, I have a client who using sage 100. We are planning to build an application for them. The requirements are: Manage customer support tickets, view and update customer details, product management, create invoices for customers, and payment capture. All these requirements need to be done through API. Is there any API documentation for sage 100 like the other products?

If not, could you please suggest how we can get/update data in sage 100 to external applications?