Scalablepress API in shopify by Revin

<!--[if gte mso 9]><xml><o:OfficeDocumentSettings><o:RelyOnVML/><o:AllowPNG/></o:OfficeDocumentSettings></xml><![endif]-->Hello,

I am new to shopify API's. I want to add scalable press API in shopify site. Do i need to Create APP for this purpose or  can we use their API direct in our shopify site. we will pay via shopify site and orders will go to scalable site. we want to use their Order API. let us how can we implement in shopify store.

Thanks and Regards,

Revin