Here you get an overview of the requirements for a minimal integration as a print partner to the cloudprinter.com print network.
The communication between Cloudprinter your API endpoint must be TLS encrypted for all live orders, so in other words HTTPS is required.
Your RESTFul API endpoint does realtime validation of the order document, or saves the order document and process's it within 15 minutes.
The following method for delivering status signals to Cloudprinter must be supported - Cloudsignal API v2.0
The following signals must be implemented - ItemRegistered - ItemShipped - ItemError - ItemCanceled
Here is a simple overview of the communication flow.